Cliffs

Many coastlines are backed by cliffs.

The cliffs vary in height, steepness and shape according to the geology of the area.

In general, cliffs increase in height over time as the coast is eroded back.

Chalk rocks tend to form vertical cliffs sometimes of great height (up to 50 metres).

The lower part of the chalk cliffs is relatively easily eroded and regular collapse of the well-jointed rocks keeps the steep profile.

Some well-jointed but more resistant limestone rocks develop overhangs.

If the rocks occur in layers, the dip of the rock also helps control steepness and form.

Beds dipping seaward can produce overhangs whilst beds dipping landward tend to produce more sloping cliffs.

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