Chalk and clay

The chalk escarpment (also known as a cuesta) is the most distinctive feature of chalk scenery in England. It consists of two parts- the scarp slope, which is steep, and the dip slope, on which the land falls away more gently. The top of the escarpment has gently rolling hills with rounded summits. There is little surface drainage and rivers are few and far between; however, in places the dip slope has been cut by deep, steep-sided, V-shaped dry valleys, which are marked landscape features. After spells of wet weather temporary streams may flow in the valleys; these are known as bournes, and this term is used in place names such as Bournemouth and Eastbourne.

Chalk outcrops along the coast often lead to high cliffs such as the famous 'white cliffs of Dover', and to prominent headlands, such as Beachy Head in Sussex and Flamborough Head in Yorkshire. Erosion around headlands can lead to the formation of caves, arches and stacks. The Needles off the north-west corner of the Isle of Wight are examples of stacks.

In contrast, the clay vale is a wide and often almost flat area of land. Surface drainage is abundant and the vale is crossed by meandering steams. At the coast, clay forms weak cliffs which slide and collapse.

There are two requirements before an escarpment can be formed...

1. Alternate outcrops of different types of rocks. One rock needs to be soft and the other needs to be more resistant to erosion.

2. Beds of rock dip at an angle to the ground surface. Instead of being horizontal, the beds were tilted by earth movements so that they lie at an angle to the surface.

These two needs are commonly met in eastern and southern England. The clay is eroded more quickly than the chalk.

As the clay is eroded down into a vale, the chalk is left standing up because of its greater resistance.

The scarp slope forms a prominent feature where the layer of chalk reaches the surface.

The dip slope is more gentle following the tilt of the beds of rock.

Settlement- Some of the earliest human arrivals to the British Isles settled on chalk escarpments. Above the village of Fulking there are signs of burial mounds (tumulus) and old defences (fort and motte bailey). The chalk escarpments were drier than the wet clay vales and contained flint which could be used for tools and weapons by the early settlers. The main problem for settlement in areas of chalk was shortage of water. Springs form at the junction of the chalk and clay; water seeping down through the spaces in the porous chalk meets the impermeable clay and reappears on the surface as a flow of water. Settlements grew along the spring line and Fulking is a classic example.

Land uses- The main land use on chalk is pasture. The short but rich turf is good for grazing sheep and training racehorses. Famous racecourses such as Epsom and situated on the Downs. High cereal prices and intesification of farming have led some farmers to plough up gentler and lower slopes for wheat and barley, despite the dry and stony nature of the chalk soils. The main land use on clay is also pasture. In general the soils are too wet and heavy to plough. The grass grows longer than that on the chalk and is more likely to be grazed by dairy cattle.

Economic uses-

Chalk with flint provides a strong and attractive building material. Chalk has many of the same economic uses as limestone, such as in the manufacture of cement. The underground stores of water, known as aquifers, are widely used for water supply in south-east England. Clay, taken from pits, is a raw material for making bricks.