COASTAL EROSION (Rotational slipping)1 2 3
Cliff failure takes place primarily by the development of large rotational slips which may extend well below sea level. There are about fourteen major slips along the North coastal section. These are lubricated by groundwater during the winter when most movement takes place. Movement is mostly slow and progressive, but occasionally very rapid slipping takes place.
In the picture above, Barrows Brook is a prime example of an arete, with a old rotational slump in the distance. To the left (East) of the arete is a new rotation event which will over the years work its way over the beach to be washed away by the sea.
Slippage on the in situ cliffs at Warden Bay

Vertical cracks typical of the London Clay. During wet weather, water runs into the cracks causing 'slip' to form. When the weight of the clay becomes critical slumping takes place along the 'slip' planes.

(Slip describes liquified clay and is a term used in ceramics)

Examples of beach heave at the junction of the cliffs and the beach
Notice the arete in the backgound. This shows collapsed clay near to the Coastguard Lookout section west of Warden Point   Rotational slippage with beach heave whole areas of the field above are affected
At some point in the progress of the rotation the overlying strata are exposed at beach level. Here there is an example of river gravels eroding onto the beach between Hens Brook and Barrows Brook. In othe sections it is possible to find brick earth, the Virginia Waters formation or the Claygate beds. All vestiges of the overlying strata.