South Downs

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The South Downs

The South Downs is the chalk cliffs which are on the southern coast of England.

Chalk is mainly in the East of the country, and runs from France right up to northern England. It was laid down in a tropical sea during the Cretaceous period. The chalk was made by tiny plankton called coccolithophores in tropical conditions.[1]

Flint is often found in the chalk, and has a different origin. It has a different structure. It is made of silica, probably made by sponges.[2]

References[change | change source]

  1. King, Hobart M. "Chalk: A biological limestone formed from shell debris". Retrieved 1 March 2021.
  2. Prothero, Donald R. 2018. The story of the Earth in 25 rocks: tales of important geological puzzles and the people who solved them. doi:10.7312/prot18260-021