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Home , Ampthill Clay, Ancholme Group, Bath stone, Bockmer End, Brickhill, Cornbrash Formation

Strategic Stone Study A Building Stone Atlas of (including )

Published August 2018 Contents

Danesfield House (Page 11)

Introduction...... 1 Buckinghamshire Bedrock Geology Map...... 2 Buckinghamshire Superficial Geology Map...... 3 Stratigraphic Table...... 4 The use of stone in Buckinghamshire’s buildings...... 5-20

Background and historical context...... 5 The Yardley to Wittlewood Ridge...... 7 The Vale of ...... 7 The Midvale Ridge...... 9 The Greensand Ridge...... 9 The Icknield Belt and Chalk Foothills...... 10 The Chilterns...... 11 The Thames Valley...... 12 Witchert...... 12 Chalk cob...... 13 Stones and in walls...... 14 ...... 17

Buckinghamshire’s indigenous building stones...... 20-31

Lower ...... 20 ...... 21 Upper Jurassic...... 22 Lower ...... 23 Upper Cretaceous...... 24 Palaeogene...... 28 Quaternary...... 29

Imported building stones ...... 32-37 Glossary...... 38 Acknowledgements and References ...... 39 Introduction

Despite its comparatively small size, Buckinghamshire has a are defined by a combination of local landscape, history, varied topographic character. This is a direct reflection of its cultural and economic activity, geodiversity and biodiversity underlying geology which principally ranges from Jurassic to (https://gov.uk/government/publications/national-charac- Cretaceous in age. The diverse geology comprises interbedded ter-area-profiles-data-for-local-decision-making). mudstones, , chalks and , many of which have been exploited to provide building materials. Stone was Parts of the following National Character Areas extend into once quarried, on a relatively small scale at many locations. Buckinghamshire: Natural stone features prominently in a large number of the NCA 88 Beds and Cambs Claylands county’s surviving historic buildings and also in other stone NCA 90 Greensand Ridge structures including canal walls, road and railway bridges, and NCA 91 Yardley - Wittlesford Ridge field and other boundary walls. Over large areas of the county, NCA 108 Upper Thames Clay Vales the bedrock succession is concealed by largely unconsolidated NCA 109 Midvale Ridge Quaternary and Recent sediments. NCA 110 Chilterns NCA 115 Thames Valley Historically, Buckinghamshire has drawn extensively on the building stone resources of neighbouring counties, which were However, the Beds and Cambs Claylands is a very large area readily transported and imported via the rivers and former that extends from the Fens to East Buckinghamshire; similarly, Roman roads. By the late C19th and early C20th a significant the Upper Thames Clay Vales extend from Bedfordshire to west proportion of the natural stone used in the developing infra- . In terms of describing the built heritage of Bucking- structures of Buckinghamshire’s larger population centres was hamshire in this Atlas, it is more meaningful to use the well-rec- also imported from sources much further afield, whether in the ognised term ‘The Vale of Aylesbury’ for the areas of those two UK or overseas. NCAs that cover the large clay vale of Buckinghamshire.

Currently Buckinghamshire is made up of 6 local authorities. The area of the Beds and Cambs Claylands that lies within Occupying the north-east of the County is the unitary authority Buckinghamshire is located to the north and east of the county of Milton Keynes which encompasses Buckinghamshire’s and includes the settlements of , Weston Under- largest and most populous town. The remainder of the County wood, Olney, the villages of Milton Keynes (such as Great falls under two tiers of administration, comprising Buckingham- Linford, Thornton, Whaddon, Old Woolverton), and the shire County Council and four District Councils. The latter are, area. The area of the Upper Thames Clay Vales from north to south, the Vale of Aylesbury District (covering the that covers part of Buckinghamshire lies to the west and south extensive low-lying area known as the Vale of Aylesbury and the of the county and stretches from in the north Mid Vale Ridge), (covering the southwestern west to Cubblington in the east. This area includes the settle- part of the Chilterns as represented in the County), Chiltern ments of Haddenham, Aylesbury, Winslow, the Claydons and District (covering the eastern part of the Chilterns as represent- Ludgershall. The Mid Vale Ridge lies between the two areas of ed in the County) and South Buckinghamshire District. The clayland that form . It extends from Whitchurch latter covers part of the Thames and Colne Valleys on the edge west into and Wiltshire and includes the settle- of West , and partly surrounds Slough. Slough itself was ments of , and Brill. historically part of Buckinghamshire but was transferred to in 1974 and it is covered within the Strategic Stone Finally, an area with a distinct landscape character and history Study Atlas for that county. of building stone use lies within and along the southern boundary of the Upper Thames Clay Vales in Buckinghamshire. Building stones in this Atlas are treated as either ‘Indigenous’ or This area is located between the foot of the White Chalk of the ‘Imported’ and are described in stratigraphic order. To assist the Chilterns scarp and the clay lands to the north. This area has reader in navigating around the Atlas, entries in the stratigraph- been called ‘The Icknield Belt and Chalk Foothills’ in this Atlas ic table that follows and the corresponding descriptions are and includes the settlements of Aston Rowant, , interactively linked (by means of small coloured triangles Princess Risborough and Halton. located in the upper right corner of the relevant pages).

The section of this Atlas summarising the use of stone in Buckinghamshire is based mainly on relevant National Charac- ter Areas which are very relevant National Character Areas which are very relevant to the vernacular built heritage as they

Buckinghamshire Strategic Stone Study 1 Buckinghamshire Bedrock Geology Map

N N OlneyOlney

WolvertonWolverton MiltonMilton Keynes Keynes

BuckinghamBuckingham ThornboroughThornborough

GreatGreat Brickhill Brickhill HoggestonHoggeston StewkleyStewkley

WingraveWingrave AylesburyAylesbury Brill Brill HartwellHartwell HaltonHalton HaddenhamHaddenham PrincesPrinces Risborough Risborough AmershamAmersham BradenhamBradenham

West WestWycombe Wycombe High WycombeHigh Wycombe 00 10 10 20 Km 20 Km Beaconsfield

MedmenhamMedmenham Iver Iver

BuckinghamshireBuckinghamshire Bedrock Bedrock Geology Geology

BUILDINGBUILDING STONE STONE SOURCES SOURCES

LONDONLONDON CLAY FORMATIONCLAY FORMATION - CLAY, - SILTCLAY, AND SILT AND SAND

LAMBETHLAMBETH GROUP - CLAY, - SILTCLAY, AND SILT SAND AND SAND

WHITEWHITE CHALK CHALK SUBGROUP SUBGROUP - CHALK - CHALK

MELBOURNMELBOURN ROCK ROCK MEMBER MEMBER - CHALK - CHALK AND AND LIMESTONE

GREY GREYCHALK CHALK SUBGROUP SUBGROUP - CHALK - CHALK

TOTTERNHOETOTTERNHOE STONE STONE MEMBER MEMBER - CHALK - CHALK AND CALCARENITE AND CALCARENITE

SELBOURNESELBOURNE GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - MUDSTONE, - MUDSTONE, SILTSTONE SILTSTONE AND AND SANDSTONE

LOWERLOWER GREENSAND GREENSAND GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - SANDSTONE - SANDSTONE AND MUDSTONE AND MUDSTONE

WEALDENWEALDEN GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - MUDSTONE, - MUDSTONE, SILTSTONE SILTSTONE AND SANDSTONE AND SANDSTONE

PURBECKPURBECK GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - LIMESTONE - LIMESTONE AND MUDSTONE AND MUDSTONE

PORTLANDPORTLAND GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - LIMESTONE - LIMESTONE AND CALCAREOUS AND CALCAREOUS SANDSTONE SANDSTONE

ANCHOLMEANCHOLME GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - MUDSTONE, - MUDSTONE, SILTSTONE SILTSTONE AND SANDSTONE AND SANDSTONE

CORALLIANCORALLIAN GROUP GROUP (UNDIFFERENTIATED) (UNDIFFERENTIATED) - LIMESTONE, - LIMESTONE, SANDSTONE SANDSTONE AND MUDSTONE AND MUDSTONE

GREATGREAT OOLITE GROUP GROUP - LIMESTONE - LIMESTONE AND ARGILLACEOUS AND ARGILLACEOUS ROCKS ROCKS

CORNBRASHCORNBRASH FORMATION FORMATION - LIMESTONE - LIMESTONE

FORESTFOREST MARBLE FORMATION FORMATION - LIMESTONE - LIMESTONE AND MUDSTONE, AND MUDSTONE, INTERBEDDED INTERBEDDED

BLISWORTHBLISWORTH LIMESTONE LIMESTONE FORMATION FORMATION AND WHITE AND WHITE LIMESTONE LIMESTONE FORMATION FORMATION (UNDIFFERENTIATED) (UNDIFFERENTIATED) - LIMESTONE - LIMESTONE

LIAS GROUPLIAS GROUP - MUDSTONE, - MUDSTONE, SILTSTONE SILTSTONE AND FERRUGINOUS AND FERRUGINOUS LIMESTONE LIMESTONE

Derived from BGS digital geological mapping at 1:50,000 scale, British Geological Survey © NERC. All rights reserved

Buckinghamshire Strategic Stone Study 2 Buckinghamshire Superficial Geology Map N Olney N Olney Milton Keynes

Buckingham Thornborough Wolverton Milton Keynes Buckingham HoggestonThornborough

Great Brickhill Aylesbury Stewkley Brill Hartwell WingraveHalton AylesburyHaddenham Brill Hartwell Amersham Bradenham Halton Haddenham PrincesWest Risborough Wycombe Beaconsfield Amersham Bradenham 0 10 20 Km High Wycombe BeaconsfieldIver 0 10 20 Km Medmenham Iver

Buckinghamshire Superficial Geology

BUILDING STONE SOURCES

BuckinghamshireALLUVIUM - CLAY, SILT, Superficial AND GRAVEL Geology

BUILDINGBRICKEARTH STONE - PEAT,SOURCES CLAYS, SILT AND SAND

ALLUVIUMHEAD - SANDS, - CLAY, GRAVELS,SILT, SANDS SILT, AND AND GRAVEL CLAY

BRICKEARTHRIVER TERRACES - PEAT, - CLAYS,SANDS, SILT GRAVELS AND SAND AND CLAY

HEADGLACIOFLUVIAL - SANDS, GRAVELS, AND GLACIOLACUSTRINE SILT, AND CLAY DEPOSITS - SANDS, GRAVELS, SILT AND CLAY

RIVERGLACIAL TERRACES TILLS - - CLAYS, SANDS, SANDS, GRAVELS GRAVELS, AND CLAY BOULDERS

GLACIOFLUVIALTUFA AND GLACIOLACUSTRINE DEPOSITS - SANDS, GRAVELS, SILT AND CLAY

GLACIALCLAY-WITH- TILLS - CLAYS, - SANDS, SANDS, GRAVELS, GRAVELS, CLAY BOULDERS AND SILT

TUFA Derived from BGS digital geological mapping at 1:50,000 scale, British Geological Survey © NERC. All rights reserved CLAY-WITH-FLINTS - SANDS, GRAVELS, CLAY AND SILT Buckinghamshire Strategic Stone Study 3 Stratigraphic Table

EPOCH/PERIOD GROUPS FORMATIONS BUILDING STONES

l Glacial pebbles and cobbles l Quaternary Flint (Field Flint, Brown Field Flint, Clay-with-Flints) l Sarsen Stone (Greywether, Denner Hill QUATERNARY Variously subdivided Variously subdivided Stone, Quartzose Sandstone, Silcrete) l False Puddingstone (Ironstone , including Iver Puddingstone and Wingrave Puddingstone varieties)

Thames Group Formation l Bradenham Puddingstone (Puddingstone, PALAEOGENE Conglomerate) Upnor Formation

Montrose Group Newhaven Chalk Formation Seaford Chalk Formation l Chalk (Chalk Block, Clunch, Rag) Lewes Nodular Chalk Formation l Flint (Fresh Flint) New Pit Chalk Formation Subgroup White Chalk Holywell Nodular Chalk Formation UPPER (incl. Melbourn Rock Member) CRETACEOUS Zig Zag Chalk Formation l Totternhoe Stone (incl. Totternhoe Stone Member at base)

West Melbury Marly Chalk Formation Subgroup Grey Chalk (incl. Cambridge Greensand Member at base)

Upper Greensand Formation Selborne Group Formation LOWER Lower Greensand Group Formation l Brickhill Ironstone (Carstone) CRETACEOUS l Whitchurch Sandstone Whitchurch Sand Formation l Bowel Stone Purbeck Formation l Purbeck Limestone (Buckinghamshire type) l Portland Limestone (Buckinghamshire type) UPPER JURASSIC Formation Formation Clay Formation

Cornbrash Formation l Cornbrash l Forest Marble Blisworth Limestone Formation l Blisworth Limestone (White Limestone) MIDDLE JURASSIC Taynton Limestone Formation Sharp’s Hill Formation Horsehay Sand Formation Group Northampton Sand Formation Whitby Mudstone Formation LOWER JURASSIC Lias Group Marlstone Rock Formation l Marlstone

Table 1. Summary (Interactive) of stratigraphical and building stone names applied to Cretaceous and Cenozoic sediments, sedimentary rocks, Jurassic sediments and sedimentary rocks in Buckinghamshire (including Milton Keynes)

Buckinghamshire Strategic Stone Study 4 The use of stone in Buckinghamshire’s buildings

The mid C13th Church of St. Laud at is built mainly from locally sourced Blisworth Limestone, the dressings include Bath Stone

Background and historical context (1133) and Notley (pre-1162) near , were large and wealthy establishments; the remainder tended to be small.

Buckinghamshire extends from the Ouse Valley and the After the Dissolution the buildings of many such communities beginnings of the Midlands landscape in the north, to the river were systematically dismantled or sold for conversion into Thames and the edge of London in the south. In between, dwellings. Some buildings survive, including Abbott’s Lodging dramatically delineated by the Chilterns scarp, are the Vale of (C15th) at Notley and the remains at Burnham Abbey (1266). Aylesbury and the Chilterns. Each area is very different in The latter were restored in 1913-15 as an Anglican nunnery. character and their historical development and the availability Stone reused from monastic buildings can be found in several and use of building stone was very varied. farms, domestic and church buildings.

Overall, the county has nearly 5900 Listed Buildings and 212 Buckinghamshire has about 200 churches with remaining Medi- Conservation Areas. The earliest surviving remains of stone- eval fabric evident. They represent the largest body of extant built buildings date from the Roman period. They include the Medieval stone buildings in the County. Most churches were Romano-British settlement at , Milton Keynes, built piecemeal or altered and extended many times. Frequent- which comprises a wharf and various stone buildings. ly, stone of varied origins from within and beyond the County was used in different periods and stages of their construction During the Medieval period religious communities had a and repair. In the north, Blisworth Limestone is the dominant significant influence on the landscape, economy and the building stone, whereas the Purbeck and Portland limestones extraction and use of building stone in the County. Over twenty were used for churches located on or near to the Mid Vale such communities are known to have existed. Missenden Abbey Buckinghamshire Strategic Stone Study 5 Ridge, as for example, at Sherington. There are a few churches From the C17th, re-facing and encasing of timber framed of ironstone on the Greensand Ridge, especially in and around manor houses using stone became fashionable as, for example, the villages of Great Brickhill and . at Little Loughton Manor near Milton Keynes.

Flint was used in most of the pre-Reformation churches to the Brick was produced at Brill on the Mid Vale Ridge from the south of the Vale of Aylesbury and in the Chilterns, often with C12th, with floor tiles being manufactured at Tyler’s Green in Totternhoe Stone (sourced from Bedfordshire) used for the the Chilterns from the C14th. In the C16th brick started to be dressings. Flint was also the main material used in the large used for prestigious houses such as Chequers and Chenies number of churches constructed in the Chilterns during the . By the C18th, brick was widely used across the C19th. Here, imported stone was often used for the dressings. County. In the Chilterns, the use of brick and flint became Sarsen Stone was used occasionally in the Chilterns and the increasingly frequent from the C18th. However, timber framing southern part of the Vale of Aylesbury. and weatherboarding continued to be used into the mid C19th.

There were no castles of great importance in the County Imported, as well as indigenous stone, was often used in the despite its strategic importance on major communication construction of and park and garden structures. Wad- routes to and from London. Timber framed construction desdon Manor for example is constructed in Bath Stone. predominated. Few stone-built structures remain, the largest was built in Ancaster Stone. Stowe has landscape being the C14th Borstall Tower (near Brill). It is the surviving gardens of international significance with a large number of gatehouse of a large moated house that was demolished stone structures and monuments. during the later C18th. Timber framing predominated in the construction of farm From the C15th, the proximity and ease of access of much of buildings across the County until the C19th, except in the north the County to London led to the development of numerous of the Vale and on the Yardley to Whittlewood Ridge. Here, mansions and estates, frequently with associated parks and stone was often used until the C18th when brick, or in the gardens. Notable concentrations are found in the Chilterns and Chilterns brick with flint, became increasingly dominant. South Buckinghamshire along the Thames Valley. They include Hampden, West Wycombe and Langley Park. Estates were also The late C19th and C20th saw the rapid expansion of London established in the Vale of Aylesbury such as Stowe, into the Thames Valley and Chilterns and the construction of and the C19th Rothschild estates of Waddesdon, Mentmore, Milton Keynes new town. Little use was made of stone in such and Halton. development apart from in occasional houses and mansions.

The impressive north-facing entrance façade of near Aylesbury, which was built between 1874 and 1889 in a Neo- style of a French château for Baron . It is constructed of Bath Stone ashlar

Buckinghamshire Strategic Stone Study 6 Gothic Revival and later the Arts and Crafts architects such as Occasionally Forest Marble and Cornbrash was also used in Devey, Voysey, Ballie Scott and Caroe often used stone. It was small quantities, for example in coursed walls at All Saints sometimes sourced from reopened historic . These Church, Ravenstone (C11th-C13th). Thatch was used as the provided Chalk, Sarsen Stone and Flint, or stone was obtained main roofing material until the C19th although stone slates from outside the County. Imported stone has continued to see were occasionally used, for example in . occasional use during the C20th and C21st, particularly for façade cladding. For example, Stoney Stratford bus station During the C19th, following deforestation and enclosure several (built in 1982-83) is faced in Cornish Granite. ‘model estate’ farmsteads, either isolated or adjacent to villages, were constructed mainly in stone. The Yardley to Wittlewood Ridge The Vale of Aylesbury The northerly part of Buckinghamshire (running approximately from Buckingham to Olney) lies on the southern fringes of the The Vale of Aylesbury is the central section of a large belt of limestone belt that runs across from to low-lying land running through south central England from . The Yardley to Wittlewood Ridge is formed of Great to Lincolnshire. In the Bedfordshire and Cambridge- Oolite Group limestone overlain by Quaternary sands, gravels shire Claylands portion of the Vale there is a relative dearth of and boulder clay. indigenous building stone. The vernacular building tradition was largely dominated by timber framing, though brick was The Ridge’s landscape history is markedly different to that of produced from the C13th, particularly in the area around the Vale of Aylesbury to the south. During the C13th, Royal Aylesbury. Hunting Forests were established at Yardley Chase, and Whittlewood. These woodlands provided important sources of fuel and building materials including timber and Great Oolite limestone.

Settlements in this area are small and relatively few, consisting largely of nucleated ‘forest villages’ located on the edge of the forest and on the lower slopes of the plateau. They include villages constructed largely of stone, such as Hartwell, Raven- stone, and . Blisworth Stone was quarried in the area (and in nearby ). It was the main stone used in a wide variety of surviving buildings dating from the C17th onwards including churches, manor houses, farm buildings, cottages, schools and village walls.

Many of the stone cottages in Sherington are constructed from blocks of locally sourced Blisworth Limestone

There are occasional outcrops of Blisworth Limestone and Cornbrash. Building stone, particularly Blisworth Limestone, was often quarried in these areas such as at Coombs Quarry near Thornborough. Quarries once existed at , Eckley, Olney and Bradwell (near Milton Keynes). Several villages around Buckingham, Milton Keynes and Newport Pagnell, such as Sherington, are constructed largely of Blisworth Limestone. Picturesque street scene in Ravenstone village showing various cottages and walls built of locally sourced Blisworth Limestone In the north east of the Claylands there are further ‘stone’ settle- with smaller amounts of Forest Marble and Cornbrash ments around and including the town of Olney. During the

Buckinghamshire Strategic Stone Study 7 Medieval period churches and structures such as bridges were Many large farmhouses survive across the Vale. Some are generally built of stone, while other buildings were usually Medieval, though most appear to date from the C16th. Typically constructed in timber frame. From the C16th onwards, many they originated as timber-framed buildings, but have been buildings, from mansions to cowsheds, were built in stone. re-fronted or encased using brick, stone or lime render.

In the south east of the Claylands area, stone from the nearby During the C17-C18th, many earlier manor houses and large Bedfordshire Greensand hills is often found in its buildings, houses were rebuilt or encased in stone. Wood, rendered brick particularly its churches. All Saints Church at Wing (C10th), one or imported stone was often used for dressings and quoins due of the finest Anglo-Saxon churches in England, and St. Michael’s to the softness of the local stone. Often the remodelling was Stewkley (C12th), the largest Norman church in the County, are extensive as, for example, at near Milton Keynes built of coursed limestone with ironstone rubble. The latter also and Hartwell House, to the west of Aylesbury. uses Quaternary glacial cobbles and pebbles. The Church of St. Peter and St. Paul in Wingrave, to the east of Aylesbury, In the north and east of the Vale, farm buildings were often built contains small quantities of Wingrave Puddingstone. in stone. During the C17th up until the mid-C18th, many new barns were built and existing barns modified to increase Across much of the Thames Clay Vale, tImber framing and processing capacity and the space available for the storage of thatch were the traditional building materials. To the north of crops. The Vale has some of the best-preserved examples of the Midvale Ridge, cruck timber frame buildings are common C18th - 19th Parliamentary enclosure landscapes in England. although stone buildings are also present in areas near to the Enclosure led to a change from arable and mixed farming to Midvale Ridge, the Cotswolds (to the west) and the Chilterns (to dairy farming which necessitated the adaption of existing the south). Occasionally villages with significant numbers of buildings or the construction of new buildings. These were stone buildings are encountered, such as Marsh Gibbon to the usually timber-framed and weatherboarded, or brick-built and north of the Ridge and Haddenham to the south. Many of roofed in Welsh Slate or plain tile. Haddenham’s buildings are constructed of Purbeck Limestone or Portland Limestone, even though the village is renowned for The Vale also contains some of the most important designed the extensive use of Witchert (described later in this Atlas). landscapes in England. They include Stowe and the group of Rothschild parks around Aylesbury, and parks such as Hartwell and Gayhurst. Extensive use was made of a range of indigenous and imported stone in their structures. The most significant garden, Stowe, has around thirty-three listed garden/park buildings in total, many in both indigenous and imported stone, including limestone ashlar and rubblestone, flint and ironstone.

Brick and tile became dominant across much of the Vale of Aylesbury from the C18th, with the rise in locally produced materials. Significant brick and tile producing industries emerged at Brill and Calvert (near Steeple ) on the Mid Vale Ridge for example, and further east at Great Linford. Improved transportation stemming from the development of canals and turnpikes and subsequently railways facilitated the spread in the use of brick and slate across the Vale from the C18th.

The C18th Green Dragon Inn in Haddenham is built mainly of Portland Limestone (Buckinghamshire type)

Buckinghamshire Strategic Stone Study 8 The Midvale Ridge A pottery and tile industry developed at Brill utilising local Whitchurch Sand and clays. It started during the Roman period and continued until the C19th. Brick was produced by a cottage Only the eastern area of the Midvale Ridge (which extends into industry from at least the C13th and expanded considerably Oxfordshire and Wiltshire) lies within Buckinghamshire; it is during the C19th. Enclosures and reorganisation of farmland encountered west of Aylesbury around Whitchurch, , during the C18th and C19th centuries saw the introduction of Waddesdon and Brill. The Ridge is formed of a discontinuous large regular fields and the construction of new farms and farm outcrop of Upper Jurassic Portland and Purbeck limestones buildings. and sandstones and capped by Lower Cretaceous Whitchurch Sandstone. The Greensand Ridge Locally quarried Portland and Purbeck limestones were commonly used as building material in villages and settlements The western end of the Bedfordshire Greensand Ridge occurs in along the ridge top or just above the low-lying ground of the southeastern Buckinghamshire. Here there is a dispersed adjacent vale. , Long Crendon, , Upper settlement pattern to the small villages that are present. Local Winchendon, Cuddington and Oving tend to have buildings building materials include the distinctive ochreous Brickhill constructed in a variety of materials including timber frame, Ironstone which was often used in local churches, village walls brick and Witchert; these often have stone plinths, although and plinths to timber-framed buildings. However, some of this complete brick or stone buildings are also common. Thatch or stone was probably sourced from nearby quarries at Heath and plain tiles are common as roofing materials, with slate becom- Reach in Bedfordshire. Amongst the best examples of the use of ing common from the C19th. Long Crendon has a substantial local Brickhill Ironstone are the churches at Great Brickhill, number of Purbeck Limestone buildings. Here stone was also Little Brickhill and where the stone is used in occasionally used to replace daub in panels in timber framed combination with Totternhoe Stone (which was employed for buildings. Other stone buildings include the Manor House (built random rubblestone walling, window and door dressings). c.1700) which has brick dressings and a C15th stone gatehouse and Notley Abbey Farmhouse.

Outlier hills capped by Lower Cretaceous Whitchurch Sand- stone occur around Brill, Whitchurch, Stone, Chilton, Waddes- don and . These red, iron-rich sandstones have been used in many of the older buildings and walls in these villages, most notably at Brill.

The C15th Church of All Saints in Bow Brickhill is built of Brickhill Ironstone with dressings of Totternhoe Stone and middle Jurassic limestone

Brickhill Ironstone was also used in the Vale of Aylesbury to the north. For example, it can be seen in Anglo-Saxon and Norman churches at Wing and Stewkley, in the C14th-C15th churches of All Saints at and St Luke at in addition to the villages of Soulbury and . The stone was particularly favoured by Gothic revival architects during the The roadside wall near The Pheasant Inn in Brill village C19th and was the main stone used in the construction of is built mainly of blocks of ochreous Whitchurch Sandstone Butterfield’s parsonage, Wavendon and Ferrey’s at Mentmore.

Buckinghamshire Strategic Stone Study 9 The C16th dovecote at , constructed of roughly squared and coursed Chalk Block and rubblestone

The Icknield Belt and Chalk Foothills Pre-Reformation churches in the area were generally built of a mixture of materials. For example, the C12th Church of All Saints at Little Kimble is constructed of variously sized knapped The Icknield Belt comprises an area of relatively low-lying hills and unknapped random flint nodules and Chalk Rag with some of Cretaceous Gault clay, Greensand and Grey Chalk which lies Sarsen Stone and Totternhoe Stone dressings. Chalk and flint between the foot of the White Chalk of the Chilterns scarp and chequerwork is displayed in the tower of St. Mary’s church at the clay lands of the Vale of Aylesbury to the north. Drayton Bauchamp, in Chequerboard Cottage at Princes Risborough and at Andersons Farmhouse near Long- Small settlements and market towns located along the foot of wick-cum-. The C16th dovecote at Monks Risborough is the Chalk scarp are characteristic of this area. They include built of Chalk Block and rubble. Princess Risborough, Monks Risborough, Great and Little Kimble, , Halton, Drayton Bauchamp, , Quarry Flint was also utilised throughout much of the area, for and . example in houses, workers’ cottages and in Medieval churches

such as the C13th Church of St. Mary at Ivinghoe. Mixed flint The area provided some Chalk Block or ‘Rag’ (from the nearby and brick is most commonly found west of Wendover. Flint was Ragpits), Sarsen Stone and Quarry Flint as used knapped and less frequently as cobbles, for example in building stone. However, the vernacular building tradition was several buildings in Weston and as the main material largely dominated by timber framing and brick which was for C19th large houses such as Ramblers, Buckland. produced and used from the C13th onwards. Farm buildings often have Chalk Rag or brick plinths and are clad in weather Sarsen Stone was also used occasionally. For example, the boarding, sometimes with stone quoins, such as at Manor impressive Church of St. Michaels and All Angels at Halton was Farm, Little Kimble. built in 1813 of squared Sarsen Stone blocks (probably sourced from High Wycombe) and exhibits large flint flake galleting.

Buckinghamshire Strategic Stone Study 10 The Chilterns Windsor. Most of the mansions were constructed of imported stone or brick, though some use was made of Chalk, Flint and Sarsen Stone. By 1820, there were approximately 600 parks The Chilterns are a range of hills that reach up to 260m AOD dating from the C17th onwards. Flint was often used for and extend from Goring on the Thames north-eastwards to structures such as Gothick cottages, gazebos, and . They are formed of Cretaceous chalk with . The Flint buildings of , where their main scarp located on the north-western side of the idiosyncratic experimental forms of flintwork were used, were outcrop. To the south of the scarp the Chilterns plateau and dip particularly influential. For example, the Dashwood Mausoleum slope fall gradually towards the Thames Valley. Here, the chalk (1764-5) West Wycombe uses decorative Flintwork for its quoins is overlain with extensive deposits of glacial clay with flints and in place of the rock-faced quoins usually used in classical other sands and gravels laid down during the Anglian glaciation buildings and the entrance to the Hell Fire Caves (1750-52) has around 400,000 years ago. The Chilterns produced five main side walls with short obelisks and a triptych façade. types of local stone: Chalk, Quarry Flint and Quaternary Flint, Sarsen Stone and Bradenham Puddingstone. During the C19th, some large estates, particularly in the south-east of the County, were split, fuelled by the demand by Timber framing with thatched roofing was dominant in the rich industrialists for new country houses that were within easy Medieval period. Flint was used in all the pre-Reformation reach of London. For example, at Medmenham (west of churches of the area and in a wide range of buildings, from Marlow) three new properties were created in 1895-6 by town houses to barns. Sometimes Sarsen Stone or Pudding- splitting the former Medmenham Abbey Estate. Two new stone was used for foundation blocks or for cornerstones. houses, Danesfield (for Robert Hudson, the soap manufacturer) and Whittington (for Hudson Kearley, founder of International There is a significant concentration of C18th and C19th Stores), were built. mansions and associated parks and gardens particularly to the south-east of the area, reflecting its proximity to London and

Danesfield House was built in 1899-1901 of Chalk Block sourced from a local quarry at Westfield

Timber framing was used for barns and other farm buildings such as hay barns, cart and implement sheds, granaries and livestock housing. They were often built on brick bases and sometimes incorporated Sarsen Stone in the footings. In conjunction with brick, Flint became the dominant building material of the area from the C18th onwards.

The C19th expansion of the railway network led to a rapid growth in population. A large number of Anglican Churches were built or rebuilt to serve the increased population. They The supposed scene of the infamous ‘Hell-Fire Club’ meetings, the C18th Hell-Fire caves at West Wycombe comprise a series were largely constructed of local Flint, often with imported of man-made caves with Flint rubble entrance and side walls stone dressings. Nonconformism became established early in

Buckinghamshire Strategic Stone Study 11 the Chilterns. There is a particularly rich legacy of C18th and Datchet. The underlying geology is mainly of London Clay C19th chapels. overlain by Quaternary alluvium and gravel deposits.

Brick was produced locally from the C15th, becoming the Historically, timber frame was dominant with brick being used dominant building material of the area from the C18th. in numerous smaller houses and farms from the late C17th Chilterns Flint was commonly used in combination with brick, onwards. Flint was also extensively used in Medieval churches especially in the central plateau areas of the Chilterns. Here, it of the area, often in combination with a range of other materi- can be found in C17th farmhouses, C18th cottages and univer- als. For example, the C11th Church of St. Peter at Iver, the C12th sally from the late C19th. Clay tiles were used as the general Church of St. Mary at Burnham and the C12th Church of St. roofing material from the C16th onwards. However, thatch Mary at Wexham variously employed locally sourced Quater- remained in use on humbler buildings. Welsh Slate became nary Flint, False Puddingstone (Ironstone conglomerate) and commonplace during the C19th due to improved transporta- Quaternary Glacial pebbles and cobbles in their construction tion, brought about by the construction of turnpikes, the Grand along with Roman brick and imported Jurassic limestones. The Junction Canal and the railway system. latter were mainly used for quoins, mullions and other decora- tive features. The Thames Valley Witchert Part of the Thames Valley, comprising the stretch of the Thames floodplain to the south of the Chilterns lies within Buckingham- Witchert (or Wytchett) literally means ‘white earth’. It is the shire. It includes the area east of Beaconsfield south to Eton name given to a local building material used in Buckingham- Wick and east to the western bank of the River Colne. Settle- shire mainly around Haddenham, Long Crendon, Chearsley, ments include Gerrards Cross, Chalfont St. Peter, Iver and Cuddington, Dinton and , east of Aylesbury. Its use also

St Mary’s Church in Burnham dates from the C12th. It is constructed mainly of Quaternary Flint with knapped Flint and occasional blocks of False Puddingstone and Glacial pebbles and cobbles

Buckinghamshire Strategic Stone Study 12 extends northwards to Ludgershall and it occurs in isolated Chalk cob pockets at and Twyford.

Chalk cob is similar material to Witchert but uses chalk as its Witchert is made from local weathered Purbeck and Portland main constituent in place of limestone. It is found in a few limestone subsoil and clay mixed with chopped straw and settlements on the north of the Mid Vale Ridge such water. When dry, the mixture provides a durable material (or as Marsh Gibbon and Grendon Underwood. An impressive cob cob) for walling. Buildings or walls made of Witchert are built wall forms the western perimeter to Burnham Abbey near on plinths of rubblestones or fieldstones, known locally as Slough. ‘grumplings’ or ‘grumblings’. These provided a damp-proof course, separating the Witchert from the ground surface and preventing groundwater ingress. In some locations, Witchert buildings were later encased in brick.

Witchert wall (and detail), Haddenham Boundary Cob wall (and detail), Burnham Abbey

Buckinghamshire Strategic Stone Study 13 Stones and fossils in walls

Buckinghamshire’s buildings and other stone-built structures display a diverse range of stones and styles of their use. A representative selection of the latter, including a range of uses of Flint, is provided in this and the following section.

Fossils used for decorative purposes are also occasionally encountered in walls. Particularly noteworthy examples include large ammonites (of Titanites type) from the Portland Lime- stone which are used in the boundary walls of Hartwell Park, and sea-urchins contained in flint nodules which feature within the walls of the Church of St. Peter and St. Paul, Iver.

Glacial pebbles and cobbles, St. Michael’s Church, Church of St. Peter, Iver

Large Titanites ammonite, wall on bridge at entrance to Sarsen Stone blockwork with Flint galletting, All Saints Church, Hartwell Park Halton

Fossil sea-urchin in flint , Church of St. Peter and St. Paul, Chalk Block ashlar, cottages Iver Buckinghamshire Strategic Stone Study 14 False Puddingstone (Wingrave Puddingstone type), Church of St. False Puddingstone (Iver Puddingstone type), Church of St. Peter and St. Paul, Wingrave Peter, Iver

Bradenham Puddingstone with Quaternary Flint nodules, St. Brickhill Ironstone, Church of St. Mary the Virgin, Great Brickhill Botolph’s Church, Bradenham

Brickhill Ironstone, Church of All Saints, Bow Brickhill Whitchurch Sandstone, wall near The Pheasant Inn, Brill

Buckinghamshire Strategic Stone Study 15 Bowel Stones with Portland Limestone (Buckinghamshire type), Flaggy laminated Purbeck Limestone (Buckinghamshire type), wall to Hartwell Park Church of St. Mary the Virgin, Haddenham

Weathered Portland Limestone (Buckinghamshire type), Church Forest Marble and Cornbrash, churchyard wall, Ravenstone of St. Mary the Virgin, Haddenham

Blisworth Limestone blockwork, Thornborough Bridge Northamptonshire Ironstone (likely imported), Church wall, Hoggeston Buckinghamshire Strategic Stone Study 16 Flint

Flint has been used in Buckinghamshire since prehistoric times. Remains of possible Neolithic Flint mines exist at High Wycombe and later workings survive at West Wycombe and Medmenham. However, Flint was mostly produced as a by-product of the quarrying of chalk for lime (Quarry Flint, Fresh Flint), or collected from field surfaces after ploughing or from recent superficial deposits (Quaternary Flint, Field Flint, Clay-with-Flints). The use of Flint in the Chilterns area conveniently demonstrates the range of types and use of this stone within Buckinghamshire as a whole.

Flint was widely used in Medieval churches from the Anglo-Saxon Built in 1763-4, the hexagonal-shaped Dashwood Mausoleum, West period onwards and in a wide range of buildings, from large Wycombe, displays a range of decorative uses of Quarry Flint and houses to barns. Mainly unworked nodules of flint, either roughly Quaternary Flint with stucco Roman Doric coursed or randomly arranged were used as wall facings in Anglo-Saxon and Norman churches often accompanied by walls constructed of Chalk Block and variously knapped flint fragments of Roman brick and a variety of stone rubble. Ashlar with oversized flint galleting. Flint galleting is relatively rare in quoins and dressings started to be introduced by the C11th and Buckinghamshire in comparison to its use in other flint-rich regular coursing started to become common after c. 1250. Flint counties such as or Berkshire. stonework was generally rendered or lime-washed during the early Medieval period. Such rendering rarely survives, but an From the middle of the C14th decorative flint work became example is provided by the C13th chancel of St. Bartholomew’s frequent in Buckinghamshire’s stone buildings. Flint was Church in . carefully selected, graded, coursed and often squared. By the C16th although church building was in decline, flint began to be used more widely in domestic buildings. Fine examples of late C16th and C17th flint work survive in, for example, the Old Manor House at Hughenden (rebuilt in 1602) and flint houses at Bockmer and Mapledurham.

During the C18th, many country estates used high quality flint work, particularly knapped and squared flints, for estate buildings. This trend continued into the C19th when terraces of cottages also started to appear, some of considerable length and uniformity. As the population increased and commons were enclosed, many small cottages of random flint rubble were built. Examples of the latter can be seen at Bradenham. The much-restored Church of St. Peter and St. Paul, Medmenham displays an impressive range of various uses of locally sourced Quarry Flint and Chalk Block. The window dressings and door During the C19th, flint and brick came to be the predominant archways are mainly of Bath Stone building materials used in the county and many churches were From the C14th, the increase in quarrying of chalk for marling mainly constructed in flint with brick or stone dressings. The and lime made Quarry Flint more readily available. Quarry Flint latter were often of limestone imported from Lincolnshire, is harder and more suited to knapping and splitting than Field Rutland or Bath. A small number of churches built during the Flint and by the C14th walls were being faced with irregular C20th in Buckinghamshire employ flint, one example being the knapped Flint. Some churches exhibit a wide range of differing Church of St Francis of Assisi at High Wycombe which was flint working techniques, for example the Church of St. Peter constructed in 1929-30. This building is flint-faced (the flint is and St. Paul at Medmenham (heavily restored in 1839) displays embedded in concrete) with freestone dressings.

Buckinghamshire Strategic Stone Study 17 Quaternary Flint nodules, Holy Trinity Church, Penn Street Mixed Quarry Flint and Quaternary Flint nodules (some knapped), Church of St. Peter, Iver

Knapped Quaternary Flint, Church of St. Peter, Iver Knapped Quarry Flint nodules, Church of St. Peter, Iver

Knapped Quarry Flint and Quaternary Flint adjoining unworked Irregular Chalk Block (Totternhoe Stone) and large Quarry Flint Quaternary Flint nodules, Dashwood Mausoleum, West Wycombe galletting, Church of St. Peter, Medmenham Buckinghamshire Strategic Stone Study 18 Chequerwork of knapped Quarry Flint and Chalk Block, Princes Decorative flintwork, Dashwood Mausoleum Risborough

Decorative flintwork, St. Mary’s Church, Burnham

Chequerwork of knapped Quarry Flint and Jurassic limestone, including Portland Limestone (Buckinghamshire type), St. Mary’s Church, Burnham

Buckinghamshire Strategic Stone Study 19 Indigenous building stones

Buckinghamshire has a varied geological succession which encom- in the area of worked ground between and Great passes strata ranging from to early Tertiary age. The Linford. northern half of the county comprises mainly Middle and Upper Jurassic sedimentary rocks, whereas the southern half of the county The very limited development of Lias Group strata in Bucking- comprises variably consolidated Cretaceous and Palaeogene depos- hamshire has resulted in its almost negligible use as a building its. In many parts of the county the bedrock has an extensive cover stone. Reports of Marlstone usage in buildings in Olney, such of largely unconsolidated Quaternary glacial deposits and Recent as the Church Hall, have not been confirmed during this study. alluvial sediments. The ironstone blocks observed in walls in Olney lack any characteristic Marlstone fossils (such as belemnites and large The bedrock succession of the county comprises a diverse sequence pectinid bivalves) and they are instead thought to originate of interbedded mudstones, sandstones, limestones, chalks with from within the Inferior Oolite Group of Northamptonshire (i.e. flints. Historically many of these rock types have been exploited to the Northampton Sand Formation) or possibly be a variant of provide local building materials and were worked at several locations Whitchurch Sandstone (see description below). within the county, albeit usually on a relatively small scale.

Blisworth Limestone from the Middle Jurassic part of the succession is still quarried at the only remaining limestone quarry in the county (Weston Underwood quarry locate near the county border with Northamptonshire). Portland Group and Purbeck Group limestones were formerly quarried at various locations in the Vale of Aylesbury including Long Crendon, Hartwell, Dinton and Cuddington. Lower Greensand Group ‘ironstones’ (Carstone) have been very locally used along the eastern border of the county, and Palaeogene -ce- mented Sarsen Stones were commonly employed as a building stone in the Chilterns. Lower Jurassic Lias Group Whitby Mudstone and Marlstone Rock formations

Marlstone

In Buckinghamshire Lower Jurassic sedimentary rocks assigned to the Lias Group are thinly developed and very poorly exposed. They crop out only to the north-west of Milton Keynes between Little Linford, and Pindon End (along the county border with Northamptonshire), but are usually concealed by unconsolidated Quaternary and Recent sediments. Where exposed, the Lias principally strata com- prise grey, variably fossiliferous, calcareous mudstones, with Olney Church Hall, built in c.1840, may contain occasional thinly interbedded paler-coloured limestones; a small ‘inlier’ of blocks of Marlstone but is constructed mainly of Blisworth Limestone and much weathered ironstone of uncertain origin orange-brown, iron-rich, sandy limestone (Marlstone) occurs

Buckinghamshire Strategic Stone Study 20 Middle Jurassic Great Oolite Group Blisworth Limestone Formation (White Limestone Formation)

Blisworth Limestone (White Limestone)

The Blisworth Limestone Formation forms part of the Great Oolite Group which is a moderately thick succession of Middle Jurassic limestones. Blisworth Limestone has been extensively worked and used as a building stone in many towns and villag- es located its outcrop in northern Buckinghamshire, notably in , Olney, Sherington, , Weston Underwood, Ravenstone, Stoke , Gayhurst, Great Linford, Stoney A section of the churchyard wall near the bus stop in Ravenstone Stratford, Thornborough and Buckingham. village showing highly laminated and rubbly limestones of the Forest Marble and Cornbrash formations in association with more ‘robust blocks’ of Blisworth Limestone and sporadic blocks of ‘ironstone’ The Blisworth Limestone Formation comprises pale yellow to pale grey, variably ooidal and bioclastic limestones which in places exhibit cross-stratification and laminations (the Forest Marble and Cornbrash formations latter become particularly pronounced towards the top of the Forest Marble, Cornbrash unit as it passes vertically upwards into the more laminated, The upper parts of the Great Oolite Group in northern Buck- flaggy and rubbly limestones of the Forest Marble and Corn- inghamshire include a thin succession of pale grey to buff brash formations). In the area to the west of Milton Keynes the coloured laminated and rubbly limestones which are assigned Blisworth Limestone Formation passes laterally into the White to the Forest Marble and Cornbrash formations. Distinguishing Limestone Formation which is lithologically similar but (as its between these limestones and those of the Blisworth Lime- name implies) is characterised by very pale coloured, whitish stone is not always easy in stone walls, but typically these coloured limestones. Such white limestones can be seen in younger limestones are more laminated and rubbly in appear- association with the ‘normal coloured’ Blisworth Limestone ance than Blisworth Limestone. The also in the nave and tower of the Church of St. Mary and St Giles in contains occasional beds packed with thick-shelled bivalve Stony Stratford. and brachiopod fossils.

The Forest Marble and Cornbrash formations have a broadly similar outcrop pattern and occurrence to the Blisworth Lime- stone Formation but tend to be less used for building than the latter. Examples of their use can be seen in Ravenstone village – especially in the walls around the churchyard and bus stop.

Thornborough Bridge dates from the C14th and is built mainly of pale grey weathered Blisworth Limestone

Buckinghamshire Strategic Stone Study 21 Upper Jurassic Limestone is employed in many towns and villages throughout central Buckinghamshire. Particularly fine examples of its use Portland Group can be seen in Cuddington, Dinton, Dunton, Haddenham, Long Formation Crendon, Oving, Whitchurch and Wing.

Portland Limestone (Buckinghamshire type) Purbeck Group Although pits dug into Portland Group strata were common in Buckinghamshire during the C20th, few exposures remain Purbeck Limestone (Buckinghamshire type) today. However, Portland Limestone and the fossils it contains In western Buckinghamshire, the Purbeck Group has a simi- (notably large ammonites of Titanites type) can be seen over lar but more limited outcrop area to the underlying Portland much of mid-Buckinghamshire where it has been extensively Group. The unit is little-developed to the east of Aylesbury. used as the building stone of local choice. The lower half of the There are currently no significant exposures of Purbeck Group Group in this area comprises mainly mustard-yellow weather- strata in the county, although historically they were worked ing sands which are too soft for building purposes; the upper at several pits, notably at Hartwell and Long Crendon. Blocks half of the Group is represented by a series of cream, buff or of Purbeck Limestone also occur as field brash on top of the pale grey to orange-grey limestones, which are sandy in places, ridges formed by Portland Group rocks at Dinton and Upper and vary from very fine-grained to gritty in texture. Some beds Winchendon. are highly fossiliferous and contain abundant small gastropods and bivalves in addition to (often large) ammonites. The Purbeck Group is relatively thin in Buckinghamshire and its occurrence in the county represents the most north-east- The buff colour and sandy nature of the Buckinghamshire erly development pf Purbeck strata in England. The succes- Portland Limestone readily distinguishes it from the whitish, sion comprises thinly bedded, fine-grained, pale grey to grey more evenly grained, homogenous Portland Stone that occurs limestones and . The limestones tend to be more flaggy on the in Dorset and which has seen use across (more laminated) in character than those of the Portland southern England. Group and they contain algal stromatolites and fossil fresh- water gastropods and bivalves. Various walls in the villages of Portland Group strata crops out in a belt extending through Cuddington and Haddenham provide some of the best exam- central Buckinghamshire from Brill, and Long ples of the use of Purbeck Limestone in the county. Crendon in the west (adjoining Oxfordshire), through , Aylesbury and to Oving and Wing in the east (near the county border with Bedfordshire). Portland

C17th stone cottages in Aylesbury Road, Cuddington built The C12th-C13th Church of St. Mary at Haddenham is constructed mainly of Portland Limestone rubblestone from a variety of Portland and Purbeck limestones

Buckinghamshire Strategic Stone Study 22 C17th-C18th cottages in Church Street, Brill are constructed from roughly coursed blocks of Whitchurch Sandstone

Cretaceous overlain by fine- to medium-grained ferruginous sandstones and ironstones; some of the sandy beds contain glauconite. The colour of the sandstones varies from greenish-grey to The Cretaceous succession that is extensively developed in deep orange-brown. The beds contain few fossils (which are the southern half of Buckinghamshire is divided into ‘Lower’ represented mainly by non-marine bivalves and gastropods). and ‘Upper’ parts. The Lower Cretaceous is represented by a lithologically varied, condensed stratigraphic succession domi- The better cemented and more durable sandstone and iron- nated by interbedded ferruginous sandstones and ironstones. stone lithologies within the formation have been used locally In contrast, the Upper Cretaceous is dominated by chalky and on a small scale as a general walling and rubblestone limestones, some of which contain flints. especially in older buildings, walls and rockeries. The village Lower Cretaceous of Brill provides some of the best examples of the use of this stone in Buckinghamshire. Here, some beds of Whitchurch Wealden Group Sandstone were sufficiently durable to be worked with the Whitchurch Sand Formation resulting blocks being used to produce roughly coursed walls. However, the softer sandstones are very susceptible to weath- Whitchurch Sandstone ering, which typically exploits laminations or areas around around harder iron-rich layers; the weathered surfaces of The oldest Cretaceous strata occurring in Buckinghamshire are isolated blocks often exhibit a purple-black colouration. assigned to the Whitchurch Sand Formation. These crop out as The Whitchurch Sand Formation crops out much more ex- a series of outliers that cap the small hills between Aylesbury tensively in the adjacent county of Bedfordshire where it was and Boarstall. The formation was formerly quarried at Long widely quarried both as an ’iron ore’ and as a building stone. It Crendon and Brill, where a thickness of 18m is developed. is therefore likely that some of the Whitchurch Sandstone used It comprises a lower succession of silts and clays, which are in Buckinghamshire was imported into the county.

Buckinghamshire Strategic Stone Study 23 Bowel Stone where Brickhill Ironstone is employed as the main walling stone, it has often been roughly worked into tabular blocks. Bowel Stone is the name given to greyish coloured, hard, The distinctive colour of this stone fabric contrasts strongly rounded, irregular siliceous that occur in the lower with the associated Chalk Block, Totternhoe Stone or Middle silty part of the Whitchurch Sand Formation. Some concretions Jurassic limestones used in the same buildings for dressings, assume quite ‘grotesque’ forms, which has obviously been irregular fill or decorative purposes. reflected in their name. Individual stones typically vary from about 20 cm to 60 cm in length, although larger stones may occasionally occur.

Bowel Stones are seldom encountered. Their use as a walling stone is sporadic and they have been employed mainly for decorative purposes. Good examples can be seen in the walls around Hartwell Park adjacent to the main between the villages of Hartwell and Stone.

The Church of St. Mary at Great Brickhill dates from the mid C13th and is built of local Brickhill Ironstone (Carstone) with Totternhoe Stone and Middle Jurassic limestone dressings

Upper Cretaceous

The Upper Cretaceous Chalk Group forms a broad belt extend- Section of the roadside wall leading to Hartwell Park, west of Aylesbury, comprising Portland Limestone with decorations of ing roughly north-east to south-west across Buckinghamshire. knapped flint and Bowel Stones This runs approximately from Princes Risborough, Medmen- ham, and Chalfont St Giles in the east, and Lower Greensand Group forms the scarp face of the Chilterns. The Chalk Group suc- cession attains a total thickness of approximately 300m and is divided into a thinner lower unit (the Grey Chalk Subgroup, or ‘Lower Chalk’, which has a relatively high clay content and Brickhill Ironstone (Carstone) contains marls but no flint) and a thicker upper unit (the White The Buckinghamshire outcrop of the Woburn Sands Forma- Chalk Subgroup, or ‘Middle and Upper Chalk’, which comprises tion is confined to a small area In the east of the county. This nearly pure chalk and contains abundant flint). area takes in the Brickhills villages and extends as far north as Woburn Sands on the county border with Bedfordshire. Chalk Group – Grey Chalk Subgroup The strata comprise distinctive red-brown, orange-brown or dark greenish-brown, highly ferruginous sandstones and Zig Zag Chalk Formation ironstones, which are typically medium- to coarse-grained. (Totternhoe Stone Member) Individual weathered blocks often exhibit liesegang banding, along with resistant purple-black coloured veins, stringers and Totternhoe Stone laminations of various iron compounds. The Totternhoe Stone Member varies in thickness from approx- imately 0.5 to 2m thickness; locally it may reach up to 5-6m, These ironstones are much used locally as a general walling but the base and top of the unit may grade into the adjoining stone and feature in many houses, roadside walls and churches chalk deposits and thus the boundaries can be difficult to in Soulbury, Stoke Hammond, Great Brickhill, Little Brickhill, recognise. Totternhoe Stone is a distinctly harder unit of chalk Bow Brickhill and (to a lesser extent) Stewkley. In local churches within the Grey Chalk Subgroup and typically comprises fine-

Buckinghamshire Strategic Stone Study 24 The north wall of Church of St. Mary the Virgin at Great Brickhill showing Totternhoe Stone (with Bath Stone repairs) employed in decorative fashion around windows and door archways. The church itself is built mainly of Brickhill Ironstone grained, creamy to pale brownish-grey, chalky calcarenites. It Chalk Group - White Chalk Subgroup often appears ‘sandy’ due to the presence of coarse fossil frag- ments. The unit varies from thin to thickly bedded and is phos- Chalk (Chalk Block, Clunch, Rag) phatic in parts; some beds contain characteristic dark brown phosphatic pellets up to a few mm across, which occasionally The white chalky limestones of the Upper Cretaceous White become nodular and attain sizes of several cm across. Chalk Subgroup are amongst the most distinctive and easily recognised building stones employed in Buckinghamshire. Overall, the use of Totternhoe Stone in Buckinghamshire appears They are white to very pale grey, typically structureless lime- to have been quite limited. Houses and other buildings con- stones, which in places contain fossil oysters (inoceramids) structed of the stone in a variety of styles can be seen at Aston and sea-urchins, and occasionally crinoids, brachiopods and Clinton, Bierton, , Hambledon, -cum-Il- belemnites. mer, Princes Risborough and Turville. Totternhoe Stone was also employed in several churches; including the Church of St. Chalk is generally unsuitable for exterior stone-work as re- John the Baptist in and St. Mary (Norman) peated wetting and drying (coupled with frost action), causes Ivinghoe, which was built on a knoll of Totternhoe Stone and the relatively soft rock to powder and disintegrate into small utilises the stone in its fabric. Totternhoe Stone was used in angular brash. Softer forms of the stone, when used externally, decorative fashion around windows and doors in churches at may show concave weathering away from mortar lines. Great Brickhill, Little Brickhill and Bow Brickhill. Chalk has been sporadically quarried as a local source of The proximity of the once-famous Totternhoe Stone quarries building stone across much of its outcrop, although its use near Dunstable in Bedfordshire has doubtless resulted in the is relatively limited. Where employed, Chalk is typically used importation of Totternhoe Stone into Buckinghamshire. For as a rough walling stone (often accompanying other stones, example, such stone was certainly used at Edlesborough. especially flint) or for decorative purposes (window dressings or banding etc.). The stone may be roughly cut, which has enabled the creation of areas of squared blockwork, but walls Buckinghamshire Strategic Stone Study 25 constructed entirely of Chalk Block are rare; an example is pro- Quarry Flint (Fresh Flint) vided by the C19th cottages at Bockmer End, Medmenham. Quarry Flint is one of the most common and widely used building stones in Buckinghamshire. It originates from bands Other noteworthy examples of the use of Chalk include the and more isolated nodules of flint that occur within the chalky Church of St. Mary at (where Chalk Block limestone beds of the White Chalk Subgroup. Quarry Flint was is used in chequerwork with Quarry Flint on the tower), Wind- dug from chalk pits and has been used extensively close to and sor Lodge off Cliveden Road near Taplow and All Saints Church within the outcrop area of this bedrock unit. at Little Kimble (which incorporates local Portland Limestone, Sarsen Stone, Quarry Flint and Chalk Rag from the nearby Quarry Flint is an extremely fine-grained (cryptocrystalline) in its construction). One of the most and hard form of silica containing microscopic, quartz-crystal spectacular uses of Chalk Block ashlar in Buckinghamshire is aggregates. It usually occurs as irregularly-shaped nodules that seen at Danesfield House (now a hotel) near Medmenham. are 10-20 cm across, or as (sub-)rounded pebbles and cobbles; occasionally, it is also found as weakly banded tabular sheets Elsewhere, especially in western and southern parts of or layers up to 20 cm thick. The colour is very distinctive; fresh Buckinghamshire, Chalk Block may have been sourced from flint nodules have a white outer cortex with a black or dark grey adjacent counties, especially south Oxfordshire or Berkshire. interior. Quarry Flint breaks with a characteristic conchoidal Documentary evidence is required to determine these sources. fracture, producing razor-sharp, fine edges; the cleaved surfac- es may exhibit banding resulting from the alternation of layers of slightly different composition. Flint nodules may contain cavities lined with translucent botryoidal chalcedony or small transparent quartz crystals; some flints contain well preserved

Late Victorian cottages built of dressed Chalk Block at Bockmer End, Medmenham. The dressings are likely Bath Stone

Buckinghamshire Strategic Stone Study 26 The C15th Church of St. Peter in Iver was heavily restored in 1848. It is constructed mainly from Quarry Flint with blocks of False Puddingstone, Glacial pebbles and cobbles and Roman tiles

fossils, with echinoids, sponges, bivalves and burrow-struc- The extremely hard and resistant nature of Quarry Flint-type tures being the most commonly encountered types. nodules has resulted in them having been recycled by natural processes into younger deposits. These reworked types of Quarry Flint is used very extensively in walls throughout Flint, which show specific characteristics, are described in the Buckinghamshire in a wide variety of ways: it is laid to course Quaternary section of this Atlas below. as rough tabular ‘sheets’ of nodules; in squared chequerwork and; as knapped, faced, trimmed or ‘cleaved-faced’ stone, both in random and decorative arrangements including pan- els. Many churches in the county employ flint in one form or another, and the stone was used extensively in many villages.

Examples of the use of Quarry Flint are provided by the Church of St. Peter in Iver, the Church of St. Mary in Burnham and the Church of St. John the Baptist in Little Marlow (the latter fea- tures a mix of Quarry and Quaternary flints). The spectacular use of Quarry Flint (and Quaternary Flint) together with Chalk Block can be seen in walls of the Church of St. Peter, Medmen- ham; here several styles of flint knapping and decoration are evident including large flint galleting. One of the more recent additions to the stone-built architecture of Buckinghamshire is the ‘ultra-modern’ Flint House constructed on the Rothschilds’ Waddesdon Estate. The house is encased in a layered fabric of white, grey and black, irregular and dressed flint nodules.

Buckinghamshire Strategic Stone Study 27 Palaeogene bly even within the same block, but typically range from 2cm to 8cm. The pebbles are cemented by relatively uniform grey Lambeth Group quartz. It is believed that this puddingstone was formed in the Upnor or Reading formations coarser-grained sediments of the Upnor or Reading forma- tions, the clustering and sorting of the pebbles indicating that Bradenham Puddingstone (Puddingstone, it may have been a fluvial or river deposit. Conglomerate) Although very hard and durable, its limited occurrence means Bradenham Puddingstone is best seen at Bradenham village that Bradenham Puddingstone is seldom used as a building where large blocks occur around the edge and roadside of the stone and when encountered it is usually found as irregular, village green. The stone is very distinctive. It is a clast-support- isolated blocks in walls. Occasional examples can be seen in ed breccio-conglomerate containing sub-rounded to sub-an- the wall fabric of the Church of St. Botolph at Bradenham and gular pebbles of flint which exhibit grey interiors or (often) in the roadside walls leading to Hartwell Park. yellow-orange cores. The size of the pebbles varies considera-

One of the large boulders of Bradenham Puddingstone on Bradenham village green

Buckinghamshire Strategic Stone Study 28 Quaternary

False Puddingstone (Ironstone Conglomerate, Iver Puddingstone, Wingrave Puddingstone)

False Puddingstone is the name given here to breccio-con- glomerates that have an overall deep purple-red colouration and contain a mixture of sub-rounded dark reddish-grey flint pebbles and angular, orange-brown clasts and flakes of flint and . The iron-rich cement is invariably deep red-purple or even blackish coloured. False Puddingstone is readily distin- guished from Bradenham Puddingstone by its overall darker The late C12th-C14th Church of St. Peter and St. Paul at Win- colour and deep red-purple iron-rich cement; Bradenham grave is built mainly of local Portland Stone with blocks of False Puddingstone is a generally paler stone and possesses greyish Puddingstone and occasional Glacial pebbles and cobbles quartz cement.

Sarsen Stone (Greywether, Denner Hill Stone, Two varieties of False Puddingstone are recognised in this Atlas: Iver Puddingstone which is clast-supported and has a higher Quartzose Sandstone, Silcrete) proportion of clasts to matrix; the clasts comprise angular Loose blocks of hard quartzitic sandstone known as Sarsen orange-brown flint or chert and are associated with occasional Stones can be found in small clusters throughout the Chil- small rounded pebbles of white quartz terns and notably in and around Denner Hill. They typically occur as rounded or elongate pebbles, cobbles, boulders or Wingrave Puddingstone which has a higher proportion of even metre-scale isolated slabs (up to 2m in length). They are matrix to clasts; the clasts comprise orange-brown flint or grey to pale brown in colour, becoming distinctly creamy-buff chert and lack white quartz pebbles when weathered, and possess a very fine-grained saccaroidal False Puddingstone is a relatively hard, durable rock but has (‘sugary’) texture comprising sub-rounded quartz grains set a scattered occurrence and does not appear to have been a within a silica matrix which is visible on fractured surfaces. very common or reliable source of building material. The best Sarsen Stones are very hard and resistant to weathering. Their examples of its use are in churches at Iver (St. Peter), Burnham surfaces are often smooth and may occasionally show poor- (St. Mary) and Wingrave (St. Peter and St. Paul). ly-defined bedding structures.

Varieties of False Puddingstone varieties as seen in blocks in church walls - Wingrave Puddingstone (left), Iver Puddingstone (right). See also page 15 Buckinghamshire Strategic Stone Study 29 The Church of St. Michael and All Angels at Halton was constructed in 1813 entirely of blocks of pale grey Sarsen Stone with small black flint flake galleting (see also image of wall on page 14)

Quarrying Sarsen Stone was once a small but thriving local Hill Sarsen Stone. The same stone was also used for kerbing or industry in the Chilterns. At Denner Hill, Sarsen Stone was origi- paving in towns such as Princess Risborough, Marlow and High nally dug rather than quarried. The stone was also extracted Wycombe. between Prestwood and Hughenden, particularly at and . One of the best examples of the use of Sarsen Stone in Buck- inghamshire is provided by the Church of St. Michael and All Sarsen Stone can be seen in buildings in the south of the coun- Angels at Halton which is constructed entirely of precisely ty at Chenies, Halton, Wendover and in villages and estates squared blocks of pale grey Sarsen Stone which is galleted near Denner Hill. In the C18th-C20th Sarsen Stone was some- with small black flint fragments in the mortar. The precision times specified by architects for major works. For example, at cutting and setting in the fabric of the Sarsen Stone blocks is Wycombe Abbey, James Wyatt refaced the house and added unique in the county. the north block (c.1803-4) in Denner Hill Sarsen Stone with flint galleting. William Caröe used the same material for his addi- Quaternary Flint (Field Flint, Brown Field Flint, tions to the Abbey, adding a chapel and music school between Clay-with-Flints) 1898 and 1926. Its widespread availability, combined with its hardness and

Sarsen Stones were also used as corner-stones, doorsteps, resistance to weathering, means that Quaternary Flint is one stepping-stones, mounting-blocks, gate-posts and plinths or of the most dominant types of building stone used in Buck- as foundation stones in churches, cottages and farm buildings. inghamshire. Many walls and buildings (especially those of Examples of Sarsen Stone plinths and footings can be seen in churches) throughout the county employ Quaternary Flint in Great Missenden (along the High Street and the Church of St. one form or another, and the stone has been used extensively Peter and St. Paul), Little Marlow (the Church of St. John the in many towns and villages. Baptist) and the Church of St Lawrence at West Wycombe. Here the tower and adjoining walls contain many blocks of Denner

Buckinghamshire Strategic Stone Study 30 Quaternary Flint typically occurs as irregularly-shaped nodules Glacial pebbles and cobbles on the field surface or in ‘Clay-with-Flints’, or as pebbles in Quaternary-aged fluvioglacial deposits that formed across river terrace gravels and other superficial deposits. The size parts of Buckinghamshire are usually thin (rarely exceeding 5m of the nodules ranges from 10-30 cm, although larger nodules in thickness) and encompass a diverse range of poorly sorted, occasionally occur. The colour is variable; less weathered flint relatively soft and unconsolidated sediments. These vary in nodules or pebbles have a cream outer cortex with darker composition but sometimes contain harder pebbles and cob- coloured (greyish) interior; weathered flints, in contrast, or bles of flint, chert, chalk, Permo- quartzitic sandstones, those that have lain in soil or superficial deposits for a long limestones and sandstones, Jurassic lime- period may be variously discoloured or bleached, and often stones, Lower Cretaceous (Greensand) ironstones (Carstone) have brown stained interiors due to the precipitation of iron and occasional igneous and metamorphic rocks. hydroxides from percolating ferruginous water. This ‘weath- ered’ appearance helps distinguish Field Flint from the much The presence of abandoned pits confirms that these deposits ‘fresher-looking’ Quarry Flint (see images on page 19). were formerly widely exploited for constructional materials mainly on a local farm or village scale. One by-product of this As a walling stone, Quaternary Flint was employed in a wide activity was the collection and use of the harder pebbles and variety of ways: as nodules or pebbles laid roughly to course; cobbles as a source of convenient stone in local buildings. as squared blocks as part of chequer-work; as knapped, faced, trimmed or cleaved faced stone in random or decorative The presence of these pebbles and cobbles in buildings in arrangements. Nodules were often selected for their shape and Buckinghamshire tends to be sporadic but good examples can size and laid in either a random or coursed manner. be seen in the churches at Stewkley (St. Michael and All Angels) and Iver (St. Peter). Notable examples of the use of Quaternary Flint include the Church of the holy Trinity at Penn Street (Quaternary Flint nod- ules laid to course), cottages along Speen Road in Hughenden and the impressive entrance to and Dashwood Mausoleum at West Wycombe. The latter makes decorative use of the juxtaposition of alternating knapped and unworked Quaternary Flint nodules.

Flint Cottage in Hughenden was constructed in the early to mid C19th The impressive Norman Church of St. Michael and All Angels at from local Quaternary Flint nodules (laid to course) and Sarsen Stone Stewkley is built from local Portland Limestone and a range of Glacial from Denner Hill (quoins) pebbles and cobbles

Buckinghamshire Strategic Stone Study 31 Imported building stones

The Church of the Holy Trinity, Wolverton (page 34)

Buckinghamshire has a long history of importing stone. Its prox- large number of new Anglican and Roman Catholic churches. imity to the freestone centres of Oxfordshire and the Cotswolds to Whilst the majority were built mainly of local Flint, imported the west, Northamptonshire, Rutland and Lincolnshire to the stones, especially Middle Jurassic limestones, were often used north and the ease of transport provided by the rivers Thames, for the dressings and steeples. Various other imported stones Thame and Great Ouse facilitated the importation of building were also used for decorative effect in churches of the Victorian materials. The development of the (1800) High Gothic, often in conjunction with brick and flint. Imported and the construction of an extensive railway network starting stone dressings were frequently used in brick buildings of the with the opening of the London to Birmingham line (in 1838 Neo-Georgian movement, particularly in public buildings that and culminating with the Great Central line in the early C20th) were constructed in the County’s rapidly expanding towns enabled further stone importation. during the C19th and C20th.

The scale of importation increased dramatically from the C17th Other types of imported building stones can be found in mid to with improved transportation. A wide range of stones was used late C19th and early C20th prestigious buildings in the larger towns. as ornamental dressings to mansions, civic buildings, churches These typically include red Permo-Triassic sandstones and and chapels. The proximity of the south east and east of the pale, yellow-brown, Middle Jurassic oolitic limestones from the County to London led to the development of large estates and Cotswolds, Bath area or Lincolnshire. Particularly distinctive is the construction of houses, especially in the southern the white Upper Jurassic Portland Stone from quarries in Dorset. Chilterns and the Thames Valley and around Aylesbury where a number of estates were purchased and improved by the A summary of the main imported building stone types (including Rothschilds. Mansions were often constructed using imported roofing slates) which have been seen in Buckinghamshire stone, including Waddesdon Manor (built of Bath Stone) and follows. Additional descriptions of imported stones relevant to (constructed of Ancaster Stone). the county can be found in several of the references listed in the Further Reading section of this Atlas and in the corresponding Between the 1850s and the 1930s, Gothic revival and ‘arts and Strategic Stone Study atlases covering the source areas of these crafts’ architects often favoured the use of local and imported various stones (especially those covering Northamptonshire, stone for churches, houses and cottages. The rapid population Lincolnshire and Rutland). growth of the C19th led to the construction of a comparatively

Buckinghamshire Strategic Stone Study 32 Sedimentary stone types

Millstone Grit Sandstone Derbyshire

Upper Carboniferous Millstone Grit Group

Hard, medium- to coarse-grained sandstone, sometimes pebbly and feldspathic, with a distinctive granular appearance and occasional flakes of white mica. Exists in various colours, ranging from pale grey and pink (especially when fresh) to buff or pale brown (particularly when weathered). Employed sporadically in Buckinghamshire and is usually associated with industrial or transport infrastructure such as bridges and walling along canals and railways.

Stony Stratford Bridge over the River Ouse constructed in 1834 from blocks of Ashover Grit (Marsden Formation) sourced from the Crick or Dukes quarries near Whatstandwell, Derbyshire

York Stone West / South

Carboniferous Pennine Coal Measures Group

Buff to pale grey or greenish grey, typically fine-grained sandstones, which are often micaceous and laminated, but occasionally show cross-bedding. Usually weathers evenly but may separate along mica-rich horizons. Mainly employed in Buckinghamshire as flagstones, paving stones or as plinths.

York Stone steps in the churchyard of St. John the Baptist, Little Marlow

Hollington Stone Staffordshire

Triassic Helsby Sandstone Formation, Sherwood Sandstone Group

A pale red to red-brown sandstone which often usually exhibits small-scale cross-bedding and sometimes ripple marks and laminations in many blocks observed in buildings. It is only occasionally employed in Buckinghamshire and has been used mainly for decorative purposes, especially as corner stones, quoins or window dressings.

The Church of St. George the Martyr, Wolverton built in 1843 and extended in 1895, demonstrating the use of Hollington Stone for decorative purposes. The main body of the church is constructed of locally sourced Blisworth Limestone. The large rose window on the West Front is built of a lower Jurassic ironstone Horton Stone, obtained from the Marlstone Rock Formation at Hornton, Oxfordshire

Buckinghamshire Strategic Stone Study 33 Attleborough Sandstone Warwickshire

Triassic Helsby Sandstone Formation, Sherwood Sandstone Group

A fine- to medium-grained, pale greenish-grey or whitish to pale brown sandstone which characteristically exhibits cross-bedding and lamination structures. Attleborough Stone is durable and resistant to weathering and its even-grained qualities make it an excellent freestone.

The Church of the Holy Trinity, Wolverton, constructed in 1809-1815 mainly of Attleborough Sandstone ashlar from Warwickshire. Local Blisworth Limestone ashlar is utilised below sill level and in the gable ends.

Ham Hill Stone (Ham Stone) Montacute, Somerset

Lower Jurassic Sand Formation (‘Ham Hill Limestone Member’), Lias Group

A medium-grained shelly limestone which is readily sawn and dressed. When freshly cut the stone has a light, golden yellowish-brown colour, but this darkens with age and weath- ering. The latter picks out the weaker, less cemented seams and cross-bedding features which are characteristic of this sandy limestone. Relatively little used in Buckinghamshire; where it has been recorded the stone is usually employed in only small amounts for decorative work and is seen to be relatively devoid of cross-bedded features.

The late C19th Lodge Cottage and gates to Wittington House near Medmenham, constructed mainly of brick with knapped flint and Ham Hill Stone chequerwork. Some of the other stone employed for ashlar work likely includes Bath Stone

Northampton Ironstone (Northampton Sandstone) Northamptonshire

Middle Jurassic Northampton Sand Formation, Inferior Oolite Group

Orange-brown coloured ferruginous, ooidal and sandy limestones which are all commonly described as ‘ironstones’. Fresh surfaces may appear dark greenish-grey in colour but they readily weather to a yellow-brown or orangish hue. Although relatively soft and often susceptible to weathering, Northamp- ton Ironstone has been widely but sporadically used as a building stone in Buckinghamshire; particularly fine examples of its use can be seen in Olney (in the Church hall and The Swan Inn along the High Street) and in Hoggeston church.

The Church of the Holy Cross, Hoggeston dates from the C12th but was largely rebuilt and restored in 1882. It is constructed mainly of Northampton Ironstone and local Portland Limestone which are coursed in places giving the appearance of polychromic banding

Buckinghamshire Strategic Stone Study 34 Ancaster Stone Ancaster, Lincolnshire

Middle Jurassic Lincolnshire Limestone Formation, Inferior Oolite Group

A medium- to coarse-grained, creamy-white to pale yellow coloured (though rather ochreous in places) ooidal and bioclastic limestone. Weathered surfaces commonly display a streaky bacon-like patterning. In Buckinghamshire, Ancaster Stone, along with other imported Inferior Oolite limestones, tends to have been used in the construction of prestigious buildings, especially for the dressings of churches or chapels.

Mentmore Towers (formerly Mentmore House) built in the early 1850s in Jacobean style of Ancaster Stone ashlar for Baron Mayer Amschel de Rothschild

Ketton Stone Rutland

Middle Jurassic Lincolnshire Limestone Formation, Inferior Oolite Group

Ketton Stone is a porous, cream to pale yellow coloured (occasionally pale pink-stained) -rich bioclastic limestone with a well sorted texture. It lends itself to being quarried in large blocks and is regarded as a high-quality freestone.

The Old County Hall in the Market Square at Aylesbury, was con- structed during the early C18th of brick with Ketton Stone quoins, cornice and parapet decorations

Weldon Stone Northamptonshire

Middle Jurassic Lincolnshire Limestone Formation, Inferior Oolite Group

When fresh, Weldon Stone is pale cream or grey coloured coloured, but it weathers to shades of yellow and buff. It is an ooidal and bioclastic limestone exhibiting cross-bedding structures. It has been employed for ashlar and decorative work, and despite being quite porous it is remarkably weather resistant.

The entrance gateway and lodges to Tyringham House, built in 1793-1797, uses Roman cement render and Weldon Stone dressings

Buckinghamshire Strategic Stone Study 35 Bath Stone Bath, NE Somerset and possibly area, Wiltshire

Middle Jurassic Chalfield Oolite Formation, Great Oolite Group

A cream to buff coloured, variably bioclastic, ooidal limestone (freestone). Much used throughout Buckinghamshire, especial- ly in Victorian new-build projects and church refurbishments, especially as ashlar and for window and door mouldings. Other similar creamy/pale-coloured oolitic limestones from the Great Oolite Group similar to Bath Stone, such as ‘Cotswolds Limestone’ were also occasionally employed in the county. A particularly noteworthy example of the use of Bath Stone is provided by Waddesdon Manor, located several miles west of Aylesbury.

Waddesdon Manor was built in in the Neo-Renaissance style of a French château between 1874 and 1889 for Baron Ferdinand de Rothschild. It is constructed mainly of Bath Stone ashlar.

Helmdon Stone material (including oyster shell debris and sea-urchin spines). Northamptonshire Rarely encountered in Buckinghamshire, but where seen it has been employed as ashlar in prestigious buildings and fine Middle Jurassic stately homes including House and . Taynton Limestone Formation, Great Oolite Group Stowe House (the home of Stowe School and former home of the A pale yellow coloured sandy limestone which typically exhibits Temple-Grenville family) was rebuilt mainly in the C17th and C18th of cross-bedding structures and contains much broken fossil Stone ashlar. It represents one of the finest examples of neo- in Britain

Blisworth Limestone (Northamptonshire types including Cosgrove Stone) Northamptonshire

Middle Jurassic Blisworth Limestone Formation, Great Oolite Group

A cream to pinkish coloured, cross-bedded limestone contain- ing granular shell debris and possessing a ‘matrix’ which varies from soft and powdery to sparry and more resistant.

This former C18th barn to Linford Manor, Great Linford (now an Arts Centre) is constructed from a mixture of locally sourced Blisworth Limestone and a pink-coloured variety of the same stone type obtained from Northamptonshire

Buckinghamshire Strategic Stone Study 36 Portland Stone (Dorset type) Isle of Portland, Dorset

Upper Jurassic Portland Stone Formation, Portland Group

A near-white or very pale coloured limestone that (in its Basebed guise at least) is typically a fine- and even-grained freestone. It has seen widespread use across Buckinghamshire, especially in urban areas in carved form, and has been used for milestones, obelisks, monuments, war memorials, gravestones, fountains and columns. Portland Stone is also employed as a high-quality walling stone and ashlar, often forming the fronts of civic buildings and banks.

The former Town Hall in Queen Vitoria Road, High Wycombe, was built in 1903-1904 from orange rubbed brick with Portland Stone outer bays and dressings etc. The roof is believed to be of Collyweston Slate Metamorphic stone types

Roofing slates Several different types of roofing slates are known to have been imported into and variously used in Buckinghamshire since at least the C19th. Welsh Slate for example, was commonly employed in many of the county’s villages and towns (e.g. Aylesbury).

Cumberland Green Slate Westmorland Slate Holly Mount in Penn was designed by C. F. A. Voysey and completed in Hartwell House was constructed in the early C17th and extended in 1907. It is constructed mainly of roughcast with Bath Stone dressings the C18th. It was reroofed in Westmorland Slate after a fire in the and a Cumberland Green Slate roof (a typical trademark of Voysey) early 1960s

Welsh Slate Early to mid C19th Flint-built cottages (with brick dressings) and Welsh Slate roofs along Speen Road, Hughenden Buckinghamshire Strategic Stone Study 37 Glossary

Ammonite: A fossil mollusc shell, typically coiled in a spiral form. Freestone: Term used by masons to describe a rock that can be cut and shaped in any direction without splitting or failing. Ashlar: Stone masonry comprising blocks with carefully worked beds and joints, finely jointed (generally under 6 mm) and set in Glauconite: A mineral composed of iron and silica. It often horizontal lines (‘courses’). Stones within each course are of the occurs in Cretaceous and Tertiary sedimentary rocks as small same height. Although successive courses may be of different greenish coloured specks or grains. It gives the green colour to heights. ‘Ashlar’ is often wrongly used as a synonym for facing stone. the rock type Greensand.

Bioturbated: Sediments that have been reworked or disturbed Ironstone: A hard cemented by iron oxide by burrowing organisms such as worms. minerals. Often dark brownish or rusty coloured.

Bivalve: A mollusc with two shells, which may be marine or Jurassic: A period of geological time that lasted from approxi- freshwater. Examples are cockles, clams, scallops, oysters. mately 145 million to 200 million years ago. Sedimentary rocks of this age are the source of a number of important types of Breccio-conglomerate: A type of Conglomerate that contains a building stone such as Northampton Ironstone, Blisworth mixture of angular and rounded rock fragments or clasts. Limestone, Portland Limestone and Purbeck Limestone.

Calcareous: A sedimentary rock containing a significant Knapped flint: Worked flint which has been fractured (cleaved) amount (10–50 %) of calcium carbonate. to reveal the interior of the nodule.

Chalk: A soft, white limestone, sometimes powdery, which was Lamination: A small scale sequence of fine layers that occur in formed at the bottom of a sea during Late Cretaceous times. sedimentary rocks.

Chert: An opaque, extremely fine-grained sedimentary rock Liesegang banding: A type of banded structure which is composed of silica (quartz). It occurs as nodules (Flint), characteristic of ironstones and iron-rich rock. In individual concretionary masses, or occasionally as layered deposits. stone blocks it is often seen as different colour patterns, typically shades of red, orange, brown or purple. Clast: An individual constituent fragment of a sedimentary rock. Massive: Describes a sedimentary rock which is homogeneous Conchoidal fracture: A smooth fracture surface, often occurring and lacks any internal structures (such as cross-bedding or in a fine-grained rock such as flint, which shows a curved ripple-marks) or fractures. pattern of fine concentric rings or ripples. Nodule: A small, hard, rounded or elliptical mass within a Conglomerate: A sedimentary rock that comprises broken up, sedimentary rock. Resembles a pebble or larger cobble. rounded rock fragments, pebbles (>2 mm), cobbles or boulders set in a finer-grained matrix. Puddingstone: A local name for Conglomerate (see above).

Cretaceous: A period of geological time that lasted from Quaternary: A period of geological time that lasted from approximately 145 million to 65 million years ago. Sedimentary approximately 2.6 million years ago to the present Day. It rocks of this age are the source of a number of important types includes the last Ice Age. of building stone such as Greensand, Flint and Chalk. Quoin: The external angle of a building. The dressed alternate Cross-bedding: A structure in the layers (beds) of a sedimentary header and stretcher stones at the corners of buildings. rock formed by the movement of water or air. The term is usually applied to sandstones and the feature itself typically Sandstone: A sedimentary rock composed of sand-sized grains resembles sets of lines which are inclined with respect to the (i.e. generally visible to the eye, but less than 2 mm in size). bedding planes or form regular arc-shaped patterns. Sarsen Stone: A very hard sandstone formed mainly of Echinoid: A type of marine organism formed of calcareous silica-cemented quartz grains. Often found as boulders or plates, commonly called a sea urchin. Often found in Chalk rounded pebbles. sediments. Sea-urchin: see Echinoid Flint: A form of very hard, micro-crystalline quartz. Typically occurs in Chalk deposits as rounded or irregular shaped masses Superficial deposits: Surface deposits and sediments of (nodules) and has a dark grey or black coloured inner ‘core’, with various types formed during the Quaternary period. a white outer ‘skin’. Buckinghamshire Strategic Stone Study 38 Acknowledgements and References

This study, written by Dr Andy King (Geckoella Ltd., Buckinghamshire and Milton Keynes. (Commissioned Report [email protected]), Phil Collins (Phil Collins Associates, CR/03/77N). 12pp. [email protected]) and Graham Lott (BGS retired) is part of Buckinghamshire’s contribution to the Strategic Stone Study, Dewey, H. & Bromehead, C. E. N. (1915). The geology of the sponsored by . country around Windsor and Chertsey. Memoirs of the Geological Survey (England and Wales). Explanation of Sheet 269. 123pp. This report incorporates data from several sources, including local geologists (Bucks Geology Group), heritage building Ellison, R. A. & Williamson, I. T. (1999). Geology of the Windsor specialists, BGS memoirs and references (listed below) along and Bracknell district – a brief explanation of the geological with independent fieldwork by the authors. Use has also been map Sheet 269 Windsor. British Geological Survey. 29pp. made of the BGS on-line lexicon of named rock units (www.bgs. ac.uk/lexicon). Green, A. H. (1864). The geology of the country round Banbury, Woodstock, Bicester and Buckingham. Memoirs of the Geological We are very grateful to Graham Lott who provided much Survey of Great Britain, Sheet 45 of the Map of the Geological information and text incorporated into this Atlas and to Survey of Great Britain. 62pp. managers at Danesfield House and Hartwell Park for permission to photograph the building. Horton, A., Shephard-Thorne, E. R. & Thurrell, R. G. (1974). The geology of the new town of Milton Keynes. Institute of Geological Designed by Colin Matthews (PaperPixels.ink). Sciences Report 74/16. 108pp.

Technical advice and editorial comments were kindly provided Horton, A., Sumbler, M. G., Cox, B. M. & Ambrose, K. (1995). by the following (in alphabetical order): Geology of the country around Thame. Memoir for 1:50 000 Don Cameron, British Geological Survey geological Sheet 237. British Geological Survey. 169pp. Nicola Lauder, Historic England Jukes-Browne A. J. & Osborne White, H. J. (1908). The geology Dr Steve Parry, British Geological Survey of the country around Henley-on-Thames and Wallingford. Chris Welch, Historic England Memoirs of the Geological Survey (England and Wales), Explanation of Sheet 254. 113pp. Clara Willett, Historic England

Chris Wood, Historic England Morigi, A. N., Woods, M. A., Reeves, H. J., Smith, N. J. P. & Marks, R. J. (2005). Geology of the Beaconsfield district - a brief explanation of the geological map Sheet 255 Beaconsfield. BGS Memoirs, Sheet Explanations British Geological Survey. 34pp. and Mineral Resource Reports Shephard-Thorn, E. R., Moorlock, B. S. P., Cox, B. M., Allsop, J. M. & Wood, C. J. (1994). Geology of the country around Leighton Aldiss, D. T. (1990). Geological notes and local details for the Buzzard. Memoir for 1:50 000 geological Sheet 220. British 1:10 000 Sheet SP92SE (Totternhoe) British Geological Survey Geological Survey. 128pp. Technical Report WA/91/51. Sherlock, R. L. & Noble, A. H. (1922). The geology of the country Barron, A. J. M. et al. (2010). Geology of the district – around Beaconsfield. Memoir of the Geological Survey (Eng- a brief explanation of the geological map Sheet 203 Bedford. land and Wales, Sheet 255). 59pp British Geological Survey. 38pp. Sumbler, M. G. (2002). Geology of the Buckingham district – a Benham, A. J. et al. (2003). Mineral Resource Information in brief explanation of the geological map Sheet 219 Buckingham. Support of National, Regional and Local planning. British Geological Survey. 34pp.

Buckinghamshire Strategic Stone Study 39 Further Reading Websites

Casey, R. & Bristow, C. R. 1964. Notes on some ferruginous Aylesbury District Council (accessed 06 March 2018) strata in Buckinghamshire and Wiltshire. Geological Magazine. Advice Note 2.3 (2014). How to look after your witchert building. 101, 116-128. https://www.aylesburyvaledc.gov.uk/sites/default/files/page_ downloads/Witchert-buildings-2.3_1.pdf Davies, R. (1983). The English Rothschilds. Collins. 264pp. Buckinghamshire Historic Environment Record (accessed 05 March Eyers, J. (1998). Geological walks in South Buckinghamshire. 2018) Rocks Afoot Field Guide Series. 48pp. Links to the register of all known archaeological and historical sites (including listed and heritage buildings) in Buckinghamshire and Eyers, J. (1999). Geological walks in North Buckinghamshire. national Heritage Gateway searches. Rocks Afoot Field Guide Series. http://old.buckscc.gov.uk/leisure-and-culture/archaeology/ historic-environment-records/ Eyers, J. (2007). Rock around Bucks. Rocks, fossils and land- scapes. 112pp. (Second revised edition due to be published Bucks Geology Group (accessed 05 March 2018) later in Spring 2018). Reports and Publications, including several leaflets describing town trails, building stones, their locations and uses which are download- Morley Davies, A. & Baines, A. H. J. (1953). A preliminary survey able from the website in pdf format. of the sarsen and puddingstone blocks of the Chilterns. http://www.bucksgeology.org.uk/bucksgeology.html Proceedings of the Geologists’ Association. 64 (1), 1-9.

Pevsner, N. (1960). The Buildings of England: Buckinghamshire. , 356pp. [Second edition, 1994 revised by Elizabeth Williamson, 832pp].

Summerfield, M. A. & Whalley, W. B. (1980). Petrographic investigation of sarsens (Cenozoic silcretes) from southern England. Geologie en Mijnbouw, 59(2), 145-153.

Whitaker, W. (1865). On the Chalk of Buckinghamshire and on the Totternhoe Stone. Quarterly Journal of the Geological Society, London. 21, 398-400.

Whitehead, J. W. R. (1967). Traditional Building Materials in the Chilterns. Oxoniensia, 32, 1-9.

Buckinghamshire Strategic Stone Study 40 Buckinghamshire Strategic Stone Study 41