The London Basin is an elongated, roughly triangular

sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subsiden ...

approximately long which underlies London and a large area of south east England, south eastern

East Anglia East Anglia is an area in the East of England, often defined as including the counties of Norfolk, Suffolk and Cambridgeshire. The name derives from the Anglo-Saxon kingdom of the East Angles, a people whose name originated in Anglia, in ...

and the adjacent

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...

. The basin formed as a result of compressional tectonics related to the Alpine orogeny during the

Palaeogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning ...

period and was mainly active between 40 and 60 million years ago.

Boundaries and shape

Spatial boundaries

The generally accepted boundaries are the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

Chalk Group The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur acro ...

escarpments An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''esca ...

of the Chilterns and

Marlborough Downs The North Wessex Downs Area of Outstanding Natural Beauty (AONB) is located in the English counties of Berkshire, Hampshire, Oxfordshire and Wiltshire. The name ''North Wessex Downs'' is not a traditional one, the area covered being better kno ...

to the north and the

North Downs The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Much of the North Downs comprises two Areas of Outstanding Natural Beauty (AONBs): the Surrey Hills ...

and Berkshire Downs to the south. To the south lie the

Weald The Weald () is an area of South East England between the parallel chalk escarpments of the North and the South Downs. It crosses the counties of Hampshire, Surrey, Sussex and Kent. It has three separate parts: the sandstone "High Weald" in the ...

and

Salisbury Plain Salisbury Plain is a chalk plateau in the south western part of central southern England covering . It is part of a system of chalk downlands throughout eastern and southern England formed by the rocks of the Chalk Group and largely lies wit ...

and to the north is the Vale of Aylesbury. The approximate western limit is in the Marlborough area of

Wiltshire Wiltshire (; abbreviated Wilts) is a historic and ceremonial county in South West England with an area of . It is landlocked and borders the counties of Dorset to the southwest, Somerset to the west, Hampshire to the southeast, Gloucestershire ...

. The eastern end merges with the

North Sea Basin The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...

, extending on land along the north

Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...

coast to

Reculver Reculver is a village and coastal resort about east of Herne Bay on the north coast of Kent in south-east England. It is in the ward of the same name, in the City of Canterbury district of Kent. Reculver once occupied a strategic location ...

and up the east coast of

Essex Essex () is a Ceremonial counties of England, county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the Riv ...

and into

Suffolk Suffolk () is a ceremonial county of England in East Anglia. It borders Norfolk to the north, Cambridgeshire to the west and Essex to the south; the North Sea lies to the east. The county town is Ipswich; other important towns include ...

, where it is overlain by

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

'Crag' deposits which cover much of eastern

and

Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the Nor ...

and are better considered as part of the North Sea Basin. The axis of the basin runs west–east from Marlborough and Newbury (Berkshire) to

Chertsey Chertsey is a town in the Borough of Runnymede, Surrey, England, south-west of central London. It grew up round Chertsey Abbey, founded in 666 CE, and gained a market charter from Henry I. A bridge across the River Thames first appeared in t ...

(Surrey) before swinging slightly north of east through

Westminster Westminster is an area of Central London, part of the wider City of Westminster. The area, which extends from the River Thames to Oxford Street, has many visitor attractions and historic landmarks, including the Palace of Westminster, B ...

, passing midway between

Chelmsford Chelmsford () is a city in the City of Chelmsford district in the county of Essex, England. It is the county town of Essex and one of three cities in the county, along with Southend-on-Sea and Colchester. It is located north-east of Londo ...

and

Southend-on-Sea Southend-on-Sea (), commonly referred to as Southend (), is a coastal city and unitary authorities of England, unitary authority area with Borough status in the United Kingdom, borough status in southeastern Essex, England. It lies on the north ...

(Essex) to the east coast between the estuaries of the Crouch and the Blackwater.Sumbler M.G. (4th Ed 1996), ''London and the Thames Valley'', British Regional Geology series, British Geological Survey, Though north of the current mouth of the Thames, this line is well to the south of the centre-line of the basin which is asymmetric, its southern limb dipping more steeply than the northern.

Geological boundaries

The Basin formed on top of the Late Cretaceous

, which is exposed on the dip slopes of the Chilterns and North Downs. Within the centre of the basin the Chalk is mainly covered by

Palaeocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pala ...

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

and younger rocks, though the chalk is also brought to the surface by localised folds and faults, for example at

Windsor Castle Windsor Castle is a royal residence at Windsor in the English county of Berkshire. It is strongly associated with the English and succeeding British royal family, and embodies almost a millennium of architectural history. The original c ...

Lewisham Lewisham () is an area of southeast London, England, south of Charing Cross. It is the principal area of the London Borough of Lewisham, and was within the historic county of Kent until 1889. It is identified in the London Plan as one ...

and

Purfleet Purfleet-on-Thames is a town in the Thurrock unitary authority, Essex, England. It is bordered by the A13 road to the north and the River Thames to the south and is within the easternmost part of the M25 motorway but just outside the Greater Lon ...

. The Chalk forms an

artesian basin An artesian aquifer is a confined aquifer containing groundwater under positive pressure. An artesian aquifer has trapped water, surrounded by layers of impermeable rock or clay, which apply positive pressure to the water contained within t ...

, with fresh water springs emerging on the bed of the

Thames The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the R ...

. In the greater part of the basin the surface rock is Eocene

London Clay The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from ...

, flanked at the margins by older deposits such as the Reading Beds. In large areas towards the western end the London Clay is overlain by rather younger deposits of the Bagshot Beds etc., forming sandy heaths.

Tectonic history

Most of the basin is underlain at depth by a block of

Palaeozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and '' ...

rocks known as the London Platform. This is separated by faulting from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145& ...

Wessex Basin (underlying the

and Hampshire Basin) to the south and the

Worcester Basin The Worcester Basin or Worcester Graben is a sedimentary basin in central England, filled with mainly Permian and Triassic rocks. It trends roughly north-south and lies between the East Malverns Fault in the west and the Inkberrow Fault in the eas ...

to the west. Vertical movements of this block have affected both deposition and structure, with the result that many of the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

rocks underlying the neighbouring Weald are not present, or are very much thinner. Rocks of

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

age are absent under London, occurring at depth only at the western edge of the basin.

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

rocks occur over a wider area to the west and south but are also absent under London itself. During Early Cretaceous times the platform was uplifted and eroded, with the erosional material deposited to the south as the

Wealden Group The Wealden Group, occasionally also referred to as the Wealden Supergroup, is a group (a sequence of rock strata) in the lithostratigraphy of southern England. The Wealden group consists of paralic to continental (freshwater) facies sedimenta ...

. Sea level rose during deposition of the

Lower Greensand Group The Lower Greensand Group is a geological unit present across large areas of Southern England. It was deposited during the Aptian and Albian stages of the Early Cretaceous. It predominantly consists of sandstone and unconsolidated sand that were ...

, but only completely covered the platform during deposition of the Gault Formation. The whole area remained submerged during much of the Late Cretaceous, though the Chalk contains levels indicating periods of erosion. During the

the south-east of England was affected by movements related to the formation of the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

(the Alpine Orogeny). One consequence of this was relative vertical movements, with the eastern part of the Wessex Basin being uplifted as the Weald-Artois Anticline and the London Platform subsiding to form the London Basin. Up to of

and

sediments were deposited in the basin. The

saw the sea retreat from the basin as global sea-level fell due to accumulation of ice sheets.

Sedimentary infill and stratigraphy

The London Basin is mainly filled with Palaeogene

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

. The lowest (oldest) unit is the

Thanet Formation The Thanet Formation is a geological formation found in the London Basin of southeastern England.Thanetian The Thanetian is, in the ICS Geologic timescale, the latest age or uppermost stratigraphic stage of the Paleocene Epoch or Series. It spans the time between . The Thanetian is preceded by the Selandian Age and followed by the Ypresian Age ( ...

age, 56–58 million years old), which rests

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

on top of the Chalk. It is composed dominantly of shallow marine sands. On top of the Thanet Formation lies the Lambeth Group, which was deposited in a

coastal plain A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Co ...

and/or adjacent shallow sea water during the late Thanetian and early

Ypresian In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian ...

ages Ages may refer to: *Advanced glycation end-products, known as AGEs *Ages, Kentucky, census-designated place, United States * ''Ages'' (album) by German electronic musician Edgar Froese *The geologic time scale, a system of chronological measuremen ...

. The Lambeth Group consists of the

Upnor Formation The Upnor Formation is a geological formation found in the London Basin of southeastern England.Woolwich Formation and the Reading Formation. The Lambeth Group is overlain by the

Thames Group The Thames Group is an Eocene lithostratigraphic group (a sequence of rock strata) which is widespread in southeast England, especially in the Hampshire Basin from Dorset through Hampshire to West Sussex and in the Isle of Wight and in the ...

, which consists of two formations. From old to young these are the

Harwich Formation The Harwich Formation is a geological formation found in the London Basin of southeastern England. It is Ypresian (early Eocene) in age. It lies unconformably on the Lambeth Group over most of its extent, but may overlie either the Thanet Formati ...

and the

London Clay Formation The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from ...

(famous for its fossils). They were deposited in shallow marine,

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

or coastal plain ( paralic)

environments Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

and were deposited during the Ypresian age (55.8 – 48.6 million years ago). On top of the Thames Group is the Bracklesham Group, which consists of the

Bagshot Formation In geology, the Bagshot Beds are a series of sands and clays of shallow-water origin, some being fresh-water, some marine. They belong to the upper Eocene formation of the London and Hampshire basins, in England and derive their name from Bagsh ...

, the Windlesham Formation and the Camberley Sand Formation. The Bracklesham Group is also composed of shallow marine (near-shore) and coastal

facies In geology, a facies ( , ; same pronunciation and spelling in the plural) is a body of rock with specified characteristics, which can be any observable attribute of rocks (such as their overall appearance, composition, or condition of formatio ...

rocks. It can be up to 140 metres thick and is of late Ypresian to

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the ...

age.

Geography

Drainage

The basin is mainly drained by the

River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...

, but does not coincide with the Thames

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

. The upper Thames cuts through the Chilterns via the

Goring Gap The Goring Gap is the narrow valley, occupied by the River Thames, between the Chiltern Hills and the Berkshire Downs. It is approximately upstream of Reading and downstream of Oxford. The river here delimits Berkshire from Oxfordshire. The vi ...

, and consequently the Thames drains parts of the

Cotswolds The Cotswolds (, ) is a region in central-southwest England, along a range of rolling hills that rise from the meadows of the upper Thames to an escarpment above the Severn Valley and Evesham Vale. The area is defined by the bedrock of J ...

Vale of White Horse The Vale of White Horse is a local government district of Oxfordshire in England. It was historically a north-west projection of Berkshire. The area is commonly referred to as the 'Vale of ''the'' White Horse'. It is crossed by the Ridgeway Na ...

and Vale of Aylesbury. The main headstream within the London Basin proper is the

Kennet Kennet may refer to: Places in the United Kingdom *Kennet, Clackmannanshire, Scotland People *Baron Kennet, a title in the Peerage of the United Kingdom * D. Mark Kennet (born 1957), American economist *Josh Kennet (born 1987), English-Israel ...

, which flows along the axis from the Marlborough area, joining the Thames at

Reading Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spell ...

. To the south rivers such as the Mole and

Medway Medway is a unitary authority district and conurbation in Kent, South East England. It had a population of 278,016 in 2019. The unitary authority was formed in 1998 when Rochester-upon-Medway amalgamated with the Borough of Gillingham to ...

, draining from the Weald, cut through the North Downs into the basin; these are presumed to date from before the erosion of the Weald dome.Clayton K. in Jones K.C.D. (Ed), ''The Shaping of Southern England'', Institute of British Geographers Special Publication 11, Academic Press, 1980, During the Pleistocene ice age the lower Thames is believed to have been diverted well to the south of its earlier course closer to the main axis of the basin, probably by the

Anglian Stage The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), ...

. The north eastern part of the basin is now drained to the

by rivers including the Crouch, Blackwater, Stour and Orwell.

Settlements

Much of the basin is urbanised. Besides the whole Greater London Urban Area of over 9.8 million people, the basin contains most of the

M4 Corridor The M4 corridor is an area in the United Kingdom adjacent to the M4 motorway, which runs from London to South Wales. It is a major high-technology hub. Important cities and towns linked by the M4 include (from east to west) London, Slough, Brackne ...

including Newbury,

Bracknell Bracknell () is a large town and civil parish in Berkshire, England, the westernmost area within the Greater London Urban Area and the administrative centre of the Borough of Bracknell Forest. It lies to the east of Reading, south of Maiden ...

Wokingham Wokingham is a market town in Berkshire, England, west of London, southeast of Reading, north of Camberley and west of Bracknell. History Wokingham means 'Wocca's people's home'. Wocca was apparently a Saxon chieftain who may ...

Finchampstead Finchampstead is a village and civil parish in the Wokingham Borough in the shire of Berkshire, England. Its northern extremity is south of Wokingham, west of Bracknell, south-east of Reading, and west of Central London. It is an affluent a ...

Maidenhead Maidenhead is a market town in the Royal Borough of Windsor and Maidenhead in the county of Berkshire, England, on the southwestern bank of the River Thames. It had an estimated population of 70,374 and forms part of the border with southern Bu ...

and

Slough Slough () is a town and unparished area in the unitary authority of the same name in Berkshire, England, bordering west London. It lies in the Thames Valley, west of central London and north-east of Reading, at the intersection of the ...

; the urbanised area to the south-west of London (

Camberley Camberley is a town in the Borough of Surrey Heath in Surrey, England, approximately south-west of Central London. The town is in the far west of the county, close to the borders of Hampshire and Berkshire. Once part of Windsor Forest, Camb ...

Farnborough Farnborough may refer to: Australia * Farnborough, Queensland, a locality in the Shire of Livingstone United Kingdom * Farnborough, Hampshire, a town in the Rushmoor district of Hampshire, England ** Farnborough (Main) railway station, a railw ...

Aldershot Aldershot () is a town in Hampshire, England. It lies on heathland in the extreme northeast corner of the county, southwest of London. The area is administered by Rushmoor Borough Council. The town has a population of 37,131, while the Alder ...

and

Guildford Guildford () is a town in west Surrey, around southwest of central London. As of the 2011 census, the town has a population of about 77,000 and is the seat of the wider Borough of Guildford, which had around inhabitants in . The name "Guildf ...

); north and south Thames-side (

Thurrock Thurrock () is a unitary authority area with borough status and unparished area in the ceremonial county of Essex, England. It is part of the London commuter belt and an area of regeneration within the Thames Gateway redevelopment zone. The ...

Tilbury Tilbury is a port town in the borough of Thurrock, Essex, England. The present town was established as separate settlement in the late 19th century, on land that was mainly part of Chadwell St Mary. It contains a 16th century fort and an anc ...

Basildon Basildon ( ) is the largest town in the borough of Basildon, within the county of Essex, England. It has a population of 107,123. In 1931 the parish had a population of 1159. It lies east of Central London, south of the city of Chelmsford and ...

Northfleet Northfleet is a town in the borough of Gravesham in Kent, England. It is located immediately west of Gravesend, and on the border with the Borough of Dartford. Northfleet has its own railway station on the North Kent Line, just east of Ebbsf ...

Gravesend Gravesend is a town in northwest Kent, England, situated 21 miles (35 km) east-southeast of Charing Cross (central London) on the south bank of the River Thames and opposite Tilbury in Essex. Located in the diocese of Rochester, it is ...

etc.); north Kent towns including Chatham,

Rochester Rochester may refer to: Places Australia * Rochester, Victoria Canada * Rochester, Alberta United Kingdom *Rochester, Kent ** City of Rochester-upon-Medway (1982–1998), district council area ** History of Rochester, Kent ** HM Prison ...

, Gillingham,

Sittingbourne Sittingbourne is an industrial town in Kent, south-east England, from Canterbury and from London, beside the Roman Watling Street, an ancient British trackway used by the Romans and the Anglo-Saxons and next to the Swale, a strip of sea separa ...

Faversham Faversham is a market town in Kent, England, from London and from Canterbury, next to the Swale, a strip of sea separating mainland Kent from the Isle of Sheppey in the Thames Estuary. It is close to the A2, which follows an ancient Briti ...

Whitstable Whitstable () is a town on the north coast of Kent adjoining the convergence of the Swale Estuary and the Greater Thames Estuary in southeastern England, north of Canterbury and west of Herne Bay. The 2011 Census reported a population of ...

, Herne Bay and

Canterbury Canterbury (, ) is a cathedral city and UNESCO World Heritage Site, situated in the heart of the City of Canterbury local government district of Kent, England. It lies on the River Stour. The Archbishop of Canterbury is the primate of t ...

; Essex towns including Brentwood,

, Braintree,

Colchester Colchester ( ) is a city in Essex, in the East of England. It had a population of 122,000 in 2011. The demonym is Colcestrian. Colchester occupies the site of Camulodunum, the first major city in Roman Britain and its first capital. Colch ...

Clacton-on-Sea Clacton-on-Sea is a seaside town in the Tendring District in the county of Essex, England. It is located on the Tendring Peninsula and is the largest settlement in the Tendring District with a population of 56,874 (2016). The town is situated ...

and

Harwich Harwich is a town in Essex, England, and one of the Haven ports on the North Sea coast. It is in the Tendring District, Tendring district. Nearby places include Felixstowe to the north-east, Ipswich to the north-west, Colchester to the south-w ...

; and towns to the north and northwest of London including

Bishops Stortford Bishop's Stortford is a historic market town in Hertfordshire, England, just west of the M11 motorway on the county boundary with Essex, north-east of central London, and by rail from Liverpool Street station. Stortford had an estimated popu ...

Harlow Harlow is a large town and local government district located in the west of Essex, England. Founded as a new town, it is situated on the border with Hertfordshire and London, Harlow occupies a large area of land on the south bank of the uppe ...

Hertford Hertford ( ) is the county town of Hertfordshire, England, and is also a civil parish in the East Hertfordshire district of the county. The parish had a population of 26,783 at the 2011 census. The town grew around a ford on the River Lea, n ...

Stevenage Stevenage ( ) is a large town and borough in Hertfordshire, England, about north of London. Stevenage is east of junctions 7 and 8 of the A1(M), between Letchworth Garden City to the north and Welwyn Garden City to the south. In 1946, Steven ...

Harpenden Harpenden () is a town and civil parish in the City and District of St Albans in the county of Hertfordshire, England. The population of the built-up area was 30,240 in the 2011 census, whilst the population of the civil parish was 29,448. Ha ...

, Hatfield,

Welwyn Garden City Welwyn Garden City ( ) is a town in Hertfordshire, England, north of London. It was the second garden city in England (founded 1920) and one of the first new towns (designated 1948). It is unique in being both a garden city and a new town and ...

Potters Bar Potters Bar is a town in Hertfordshire, England,in the historic County of Middlesex Hertsmere Borough Council – Community Strategy First Review (PDF) north of central London. In 2011, it had a population of 21,882. In 2022 the population was ...

St Albans St Albans () is a cathedral city in Hertfordshire, England, east of Hemel Hempstead and west of Hatfield, north-west of London, south-west of Welwyn Garden City and south-east of Luton. St Albans was the first major town on the old Roman ...

Luton Luton () is a town and unitary authority with borough status, in Bedfordshire, England. At the 2011 census, the Luton built-up area subdivision had a population of 211,228 and its built-up area, including the adjacent towns of Dunstable an ...

and

High Wycombe High Wycombe, often referred to as Wycombe ( ), is a market town in Buckinghamshire, England. Lying in the valley of the River Wye, Buckinghamshire, River Wye surrounded by the Chiltern Hills, it is west-northwest of Charing Cross in London, ...

References

Literature

*; 2006: ''The geology of England and Wales'',

Geological Society of London The Geological Society of London, known commonly as the Geological Society, is a learned society based in the United Kingdom. It is the oldest national geological society in the world and the largest in Europe with more than 12,000 Fellows. Fe ...

(2nd ed.), . *; 2004: ''A Geologic Time Scale 2004'',

Cambridge University Press Cambridge University Press is the university press of the University of Cambridge. Granted letters patent by King Henry VIII in 1534, it is the oldest university press in the world. It is also the King's Printer. Cambridge University Pr ...

. *; 2008: ''Bedrock geology UK south. An explanation of the bedrock geology map of England and Wales – 1:625,000 edition'', Keyworth, Nottingham,

British Geological Survey The British Geological Survey (BGS) is a partly publicly funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its continental shelf by means of systematic surveying, monitoring and research. The BGS hea ...

, . {{Coord, 51.764, 0.445, type:landmark, display=title Geography of London Geology of London Natural regions of England Paleogene England Sedimentary basins of Europe