Editing Beachy Head (section)

==Geology==
The chalk was formed in the [[Late Cretaceous]] epoch, between 66 and 100 million years ago, when the area was under the sea. During the [[Cenozoic]] Era, the chalk was [[tectonic uplift|uplifted]] (see [[Geology of England#Cenozoic era|Cenozoic Era]]). When the [[Last Glacial Period|last ice age]] ended, sea levels rose and the [[English Channel]] formed, cutting into the chalk to form the dramatic cliffs along the Sussex coast.

Wave action contributes to the erosion of cliffs around Beachy Head, which experience frequent small rock falls. Since chalk forms in layers separated by contiguous bands of flints, the physical structure affects how the cliffs erode. Wave action undermines the lower cliffs, causing frequent slab failures – slabs from layers of chalk break off, undermining the upper parts of the cliffs, which eventually collapse.<ref>{{cite web|url=http://www.alanmackenziephotography.com//2008/09/beachy-head.html|title=ALAN MACKENZIE}}</ref> In contrast to small rock falls, mass movements are less common. A mass movement happened in 2001 when, after a winter of heavy rain, the water had begun to seep into the cracks which had frozen and caused the cracks to widen. This then made the cliff edge erode and collapse into the sea, destroying a well-known chalk stack called the Devil's Chimney.<ref>[https://www.independent.co.uk/environment/cold-wet-winter-blamed-for-cliff-collapse-at-beachy-head-5364799.html Cold, wet winter blamed for cliff collapse at Beachy Head], Michael McCarthy, ''The Independent'', 5 April 2001 (retrieved 4 September 2020)</ref>