Geology of Kent into northern France. The fold arises from the continuing Alpine orogeny and results in the general northward dip of the rock strata in most of Kent. There are extensive spreads of coastal and estuarine alluvium on the Thames Estuary coast, in the low ground surrounding the Isle of Thanet and across Romney Marsh. Alluvium also floors the valleys of the River Medway and Stour. 'Clay-with-flints' is a commonly occurring deposit across the North Downs which is a product of periglacial conditions during the last ice age. Loessic deposists, of aeolian origin i.e. windblown, are common in east Kent, especially on
Whitstable and South Street at the south. Chestfield has its own parish council. An area of protected woodland and grassland called Duncan Down lies to the south-east. The geology of the town consists mainly of London Clay (which covers most of North Kent). Much of the centre of the town is built on low-lying marshland. Sea walls are in place to prevent coastal flooding. The land in the east is higher, with slopes down to the coast at Tankerton. The whole of the north-east Kent coast has been designated a Site of Special Scientific Interest. A very unusual (some say unique)