on the southern edge of
Windsor Great Park All of the county is drained by the Thames. Berkshire divides into two topological (and associated geological) sections: east and west of
Reading. North-east Berkshire has the low calciferous (limestone) m-shaped bends of the Thames south of which is a broader, clayey, gravelly former watery plain or belt from Earley to Windsor and beyond, south, are parcels and belts of uneroded higher sands, flints, shingles and lightly acid soil and in the north of the
Bagshot Formation, north of
Surrey and
Hampshire.
Swinley Forest (also known as Bracknell Forest),
Windsor Great Park, Crowthorne and Stratfield Saye Woods have many pine, silver birch, and other lightly acid-soil trees. East of the grassy and wooded bends a large minority of East Berkshire's land mirrors the clay belt, being of low elevation and on the left (north) bank of the
Thames: Slough, Eton, Eton Wick, Wraysbury, Horton, and Datchet. In the heart of the county Reading's northern suburb Caversham is also on that bank, but rises steeply into the
Chiltern Hills. Two main tributaries skirt past Reading, the
Loddon and its sub-tributary the
Blackwater draining parts of two counties south, and the Kennet draining part of upland Wiltshire in the west. Heading west the reduced, but equally large, part of the county extends further from the Thames which flows from the north-north-west before the
Goring Gap; West Berkshire hosts the varying-width plain of the
River Kennet rising to high chalk hills by way of and lower clay slopes and rises. To the south, the land crests along the boundary with Hampshire; the highest parts of South-East and Eastern England taken together are here. The highest is
Walbury Hill at . To the north of the Kennet are the
Berkshire Downs. This is hilly country, with smaller and well-wooded valleys: those of the
Lambourn,
Pang, and their Thames sub-tributaries. The open upland areas vie with
Newmarket, Suffolk for
horse racing training and breeding centres and have good fields of barley, wheat, and other cereal crops.
Geology Berkshire’s surface can be divided into three bands: the county's
downlands, south and east of which the
London Clay spans almost the whole county, and in the south-east corner sandy
Palaeogene heath covers the London Clay. This is an oversimplification, however. A gently folded succession of
sedimentary rocks dating from the
Cretaceous period, with some surviving Palaeogene cover and extensive
Quaternary deposits, characterise the downlands, which cover the area to the west of
Reading and the western edge of the
Chiltern Hills. The lower (early) Cretaceous rocks are
sandstones and
mudstones (now visible only on the slopes of
Walbury Hill) whilst those of the upper (late) Cretaceous are the various formations that comprise the
Chalk Group. In Berkshire,
White Chalk Formation beds tend to be shallower than those further west (
Wiltshire) or those in the Chilterns, and often contain layers of chalk rock. Less consolidated Palaeogene
clays,
sands,
gravels and
silts of the
Lambeth,
Thames and
Bracklesham Groups overlie these rocks in some areas. These hills, and the valleys that surround them, were shaped by the rivers
Kennet,
Lambourn, Pang and
Enborne, and the Quaternary sands and gravels they brought with them and (in the case of the Kennet) left behind when they changed course. The early
Eocene London Clay (Thames Group) generally gets thinner as we proceed westwards, though the thickness of beds can vary considerably over short distances. Where rivers have cut through these beds Lambeth Group layers are found (notably, the
Palaeocene Reading Formation, used for brick-making since Roman times but now increasingly scarce in the area after which it was named). The heaths and woodland south and east of
Bracknell are mostly covered by (Eocene) Bracklesham Group sands and clays, and Quaternary sands, silts and gravels. After the
Thames broke through the
Goring Gap that river and its tributaries the
Loddon,
Emm Brook,
Blackwater and (to some extent)
Wey shaped the geography of eastern Berkshire but have not yet eroded away its Eocene cover. ==Governance==