Our changing Presenting… display offers a look at highlights, themes and topical material drawn from the Museum’s collections. The current display presents a rich selection of fossils taken from a formation known as the Gault Clay. This will be on show until 21 September (Madagascar is up next), so it’s almost your last chance to see it.
The Gault Clay is known for its exceptional diversity of fossils. Deposited across northern Europe in the Lower Cretaceous, 100-112 million years ago, its abundance of ammonite fossils shows that it was laid down in a marine environment, at a time when sea levels were rising rapidly.
Best seen at Folkestone in Kent, the Gault is sandwiched between the Lower Greensand and Chalk formations. The Folkestone Warren landslip has provided ample opportunities for fossil collectors for centuries. The land is still on the move today, but 100 years ago, on 19 December 1915, a major slip occurred which shut down the local railway for five years.
William Smith (1769-1839), who published the first geological map of England and Wales 200 years ago this year, called the Gault ‘blue marl’. He used the fossils found in it to map the Gault across the South of England.
Along with ammonites, it is possible to find snails, clams, shark’s teeth, fish, crabs, and lobsters. Even dinosaur fossils have been found, including the ankylosaur Anoplosaurus.
Some of the Gault collections in the Museum date back to the 1800s; others were collected as recently as 2015.