The South Downs are a range of chalk hills that extends for about 260 square miles (670 km2) across the south-eastern coastal counties of England from the Itchen Valley of Hampshire in the west to Beachy Head, in the Eastbourne Downland Estate, East Sussex, in the east. The Downs are bounded on the northern side by a steep escarpment, from whose crest there are extensive views northwards across the Weald. The South Downs National Park forms a much larger area than the chalk range of the South Downs and includes large parts of the Weald.
The Chalk Group is the lithostratigraphic unit which contains the Late Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur across the wider northwest European chalk 'province'. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment.
The geology of Hampshire in southern England broadly comprises a gently folded succession of sedimentary rocks dating from the Cretaceous and Palaeogene periods. The lower (early) Cretaceous rocks are sandstones and mudstones whilst those of the upper (late) Cretaceous are the various formations which comprise the Chalk Group and give rise to the county's downlands. Overlying these rocks are the less consolidated Palaeogene clays, sands, gravels and silts of the Lambeth, Thames and Bracklesham Groups which characterise the Hampshire Basin.
Twyford is a village and civil parish in Hampshire, England, approximately three miles south of Winchester and near the M3 motorway and Twyford Down. In 2001, the population of the parish was 1,456. The village and parish are on the left bank of the Itchen, which passes through nearby watermeadows, and has been important economically for its residents.
Owslebury is a village and civil parish in the county of Hampshire, in the south of England approximately 5 miles (8.0 km) outside Winchester. It lies within the administrative district of the City of Winchester.
Compton and Shawford is a civil parish in the City of Winchester, Hampshire, England. The word compton means village in a combe and aptly describes the settlement as it primarily consists of a long street on the side of a chalk valley.
Chilcomb is a small village and civil parish in the English county of Hampshire 3 miles (4.8 km) east of Winchester and includes the South Downs Way long distance footpath.
St. Catherine's Hill is a small but dramatic chalk hill to the south east of Winchester in Hampshire, England. Rising steeply some 67 metres (220 ft) from the water meadows of the River Itchen, the summit of the hill at 97 metres (318 ft) provides a fine view over Winchester.
The London Basin is an elongated, roughly triangular sedimentary basin approximately 250 kilometres (160 mi) long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea. The basin formed as a result of compressional tectonics related to the Alpine orogeny during the Palaeogene period and was mainly active between 40 and 60 million years ago.
The Hampshire Basin is a geological basin of Palaeogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex. Like the London Basin to the northeast, it is filled with sands and clays of Paleocene and younger ages and it is surrounded by a broken rim of chalk hills of Cretaceous age.
The geology of East Sussex is defined by the Weald–Artois anticline, a 60 kilometres (37 mi) wide and 100 kilometres (62 mi) long fold within which caused the arching up of the chalk into a broad dome within the middle Miocene, which has subsequently been eroded to reveal a lower Cretaceous to Upper Jurassic stratigraphy. East Sussex is best known geologically for the identification of the first dinosaur by Gideon Mantell, near Cuckfield, to the famous hoax of the Piltdown man near Uckfield.
Henwood Down is one of the highest points in the county of Hampshire, England, and in the South Downs, reaching a height of 201 metres (659 ft) above sea level. Its prominence of 64 metres qualifies it as a Tump.
The Dean Hill Anticline is an east-west trending fold in the Cretaceous chalk of Hampshire. It lies immediately to the north of the Hampshire Basin and south of Salisbury Plain.
The Alderbury-Mottisfont Syncline is an east-west trending fold in the Cretaceous chalk of Hampshire. It lies to the north of the Dean Hill Anticline and south of Salisbury Plain.
The geology of West Sussex in southeast England comprises a succession of sedimentary rocks of Cretaceous age overlain in the south by sediments of Palaeogene age. The sequence of strata from both periods consists of a variety of sandstones, mudstones, siltstones and limestones. These sediments were deposited within the Hampshire and Weald basins. Erosion subsequent to large scale but gentle folding associated with the Alpine Orogeny has resulted in the present outcrop pattern across the county, dominated by the north facing chalk scarp of the South Downs. The bedrock is overlain by a suite of Quaternary deposits of varied origin. Parts of both the bedrock and these superficial deposits have been worked for a variety of minerals for use in construction, industry and agriculture.
The Portsdown Anticline is a north-facing geological fold of Tertiary age affecting rocks in Hampshire, southern England. This upfold of the local sedimentary rock sequence is paralleled by the Bere Forest/Chichester Syncline (downfold) about 2km to its north and a postulated deep fault to the north again. Further west, this major east-west structure adopts more of a NW - SE alignment. At the surface the Portsdown Anticline is seen to affect the Chalk rocks of Late Cretaceous age at Ports Down though it is known to also affect the underlying Jurassic strata.
