The geology of south-east England is indicated in outline in Fig. 4. The outcrop of the Chalk, corresponding to Upper Cretaceous in Table 1, gives rise to tracts of high ground that constitute the physiographical backbone of south-east England. In the north-west are the Berkshire Downs and the Chiltern Hills, west and north-east respectively of the River Thames. Beyond the Chiltern scarp, south-easterly dipping Upper Jurassic beds form the Vale of Aylesbury and the Oxford Clay vale; farther north-west, Middle Jurassic limestones give rise to high ground, the northerly continuation of the Cotswold Hills.

The Chiltern dip-slope declines south-eastwards into the London Basin, a downfold with Tertiary clays and sands occupying its centre. The Chalk reappears south of the London Basin as the North Downs, between which and the South Downs lies the Weald, an east-west anticlinal, or upfolded area. The Weald contains a thick development of Lower Cretaceous sandstones and clays, which are largely missing beneath the Chalk of the Chilterns, where the only Lower Cretaceous formation with a continuous outcrop is the Gault clay, the youngest in the sequence. The folds of the Weald continue westwards, less strongly marked, into the wide Chalk outcrop of the Salisbury Plain. To the south lies the Hampshire Basin, like the London Basin a syncline with Tertiary beds at its centre. Its southern limit is the narrow Chalk ridge, breached by marine erosion, running through the 'Isle' of Purbeck and the Isle of Wight.

In northern parts of Oxfordshire and Bedfordshire, and in northern Essex, Jurassic to Tertiary strata are covered by extensive glacial deposits, mainly Boulder Clay, laid down towards the southern limit of ice sheets that at one time or another in the Quaternary era covered much of the Midlands and East Anglia.

Table 1 shows the relation between chronostratigraphical divisions (as in Fig. 4), based on geological age, and lithostratigraphical divisions of Group and Formation status represented in south-east England.

STONE TYPES USED FOR THE SCULPTURES

The various types of stone used for sculptures are described in stratigraphical order. Geological formations may, of course, contain other beds than those of building (or sculptural) stone quality: not all the Taynton Stone (or Taynton Limestone) Formation, for instance, is made up of Taynton stone (with a small 's'). The nature of the formation none the less determines the characteristics of the type of stone, both in this case and in those of other formations that contain stone types with local names (for instance Reigate stone, Quarr stone) acquired long before the advent of geological classification.

Both sandstones and limestones were brought into use, and most in each category were arenites, i.e. having sand-sized particles. Arenites lie within the total size-range 0.06–2 mm diameter. Fine-grained arenites have particles up to 0.2 mm diameter, medium-grained 0.2–0.6 mm, and coarse-grained from 0.6–2 mm. For identification, the stone of each sculpture was examined by hand lens with a built-in measuring grid, allowing the diameter of grains above 0.1 mm to be measured with confidence.

Much of the stone, at least for the earlier Anglo-Saxon sculptures in south-east England, probably came from Roman ruins. The distribution of stone types (Fig. 5) may therefore owe much to Roman building activity. The two main types of stone, both of them oolitic limestones, came from outside the area, one, Barnack stone, from the Inferior Oolite of Northamptonshire and Lincolnshire, the other, Bath stone, from the Great Oolite of the vicinity of Bath. In addition, some fifteen types of stone from localities in south-east England were used. Three varieties came from northern France: Caen stone, Marquise oolite, and Calcaire Grossier limestone. A few carvings are of stone of uncertain provenance.

Inferior Oolite Group, Lincolnshire Limestone Formation (Barnack stone)

A number of sculptures in northern parts of Essex, Hertfordshire, and Bedfordshire, and some in and around London, are of a shelly oolitic limestone from the upper part of the Lincolnshire Limestone, i.e. from the Sleaford Member or Clipsham Member as defined by Ashton (Ashton 1980), together equivalent to the Upper Lincolnshire Limestone of current Geological Survey usage (1:50,000 Geological Map, Grantham Sheet 127). The Lincolnshire Limestone contains various types of building stone. Two of them, Ketton stone and Ancaster Freestone, are composed of compacted ooliths with little interstitial matrix; another, Ancaster Rag, is a very shelly oolite with conspicuous calcite cement. The texture of the Lincolnshire Limestone of Anglo-Saxon sculptures in the south-east lies between these two extremes. Stone of this type in Roman and Anglo-Saxon contexts is generally called Barnack stone, after the village of Barnack near Stamford, where quarries were active in Roman times and from the later part of the Anglo-Saxon period up to the fourteenth century, when the stone became worked out. The stones here described have enough features in common to suggest that they came from one sedimentary unit, and such geological evidence as exists is consonant with this having been of limited geographical extent, and sited at Barnack.

The stone of the sculptures has a rather drab, pale yellowish grey to brownish grey colour, with ooliths around 0.4 mm diameter (ranging from 0.3–0.6 mm) and worn shell detritus of 5–10 mm diameter in a crystalline calcite matrix. Among the shell debris, ostreid fragments and (at Cardington and Hadstock) fragments of spired gastropods were noted. Planar bedding is common; some stones show low-angle cross-bedding. White Notley consists of alternate planar layers of oolite (0.3 mm ooliths) and coarser shelly oolite (0.5–0.6 mm ooliths). Many of the blocks are large (89 cm in length at Cardington and 180 cm at Milton Bryan), without being more than 30 cm in thickness. Calcite veinlets, a regular feature of Bath stone, are absent.

Great Oolite Group, Great Oolite Formation (Bath stone)

Bath stone was the most commonly used stone for Anglo-Saxon sculptures in the area considered in this volume, principally at Winchester, but occurring as far east as Godalming, Surrey, and London (All Hallows by the Tower nos. 1 and 3), with isolated examples at Canterbury (St Augustine's abbey nos. 1 and 9).

Bath stone is, like Barnack stone, a shelly oolitic limestone. It is, however, geologically younger, and accumulated in a different basin of deposition. It has generally a greyish yellow to yellow-brown colour (10YR 8/2–3), warmer than the drab yellowish grey of Barnack stone; this could result from different proportions of pyrite or other iron minerals in the matrix. Bath stone commonly has a notable content of larger ooliths (0.7 mm) than has Barnack stone, and includes conspicuous ovoid pellets up to 0.9 mm in length. In Bath as in Barnack stone, the ooliths are set in a crystalline calcite matrix. A common feature of Bath stone in particular is that weathered surfaces have a honeycomb-like appearance, being pitted by vacant hollows that once held ooliths. One of the few Bath stone sculptures with well-developed planar bedding is the large Crucifixion figure at Langford, Oxfordshire (no. 2). The main distinguishing feature of Bath stone is the presence of calcite veinlets 1–2 mm in width, cutting across the bedding, and spaced from 150–600 mm or more apart. They are known to quarrymen as 'watermarks' or 'snailcreep'.

Green and Donovan showed that the Great Oolite Formation of the Bath area includes three distinct bodies of workable Bath stone, from below upwards the Combe Down Oolite, the Bath Oolite and (in the Upper Rags division) the Ancliff Oolite (Green and Donovan 1969). The stone used for Anglo-Saxon sculpture seems to have been largely Combe Down Oolite.

The Combe Down Oolite is up to 17 metres thick at Bath and near Box, 9 km north-east of the city (Fig. 6, based on Penn and Wyatt 1979, fig. 11). The worked freestones, with commercial names Odd Down Stone, Combe Down Stone, Box Ground Stone and St Aldhelm's Stone, occur in the upper half of the Combe Down Oolite in the area where it is thickest. The Bath Oolite, which includes such varieties as Bathampton, Farleigh Down, Stoke Ground, Westwood Ground and Winsley Ground stones, is less shelly, has ooliths of a smaller size-range, and is less weather-resistant than typical Combe Down Oolite. The Ancliff Oolite (Bethel Stone, Bradford Ground Stone), invariably contains layers of shell debris and of worn polyzoan fragments (Green and Donovan 1969, 19, 21); the sundial at Hannington, Hampshire, is of this character.

Great Oolite Group, Taynton Stone (or Taynton Limestone) Formation (Taynton stone)

The Taynton Stone Formation is composed largely of shelly oolitic limestones, quarried in the valley of the river Windrush, a tributary of the upper Thames (Worssam and Bisson 1961). Slightly different varieties of the building stone, such as Burford stone and Windrush stone, were named after the particular locality where quarried, but all have the same geological character. Sellwood and McKerrow have described the formation as made up of underwater-dune deposits of a shallow open-shelf sea (Sellwood and McKerrow 1974).

Quarries at Taynton are mentioned in Domesday Book. If the exterior stonework of Taynton church (fourteenth century) can be taken as typical of Taynton stone, then this is a yellowish cross-bedded oolite, with shell fragments tending to be concentrated in calcite-cemented streaks that stand out on weathered surfaces as ribs or 'bars' (Arkell 1947, 77). The grain size for the most part is variable, with ooliths from 0.2 up to 0.6 mm. 'Watermarks' are rare: about one per cent of the stones on the church exterior show them.

Sculptures from Abingdon and Sonning in Berkshire, and from Oxfordshire at Langford (no. 1), Oxford (St Michael 2), and Lewknor, as well as baluster shafts in the church towers at North Leigh and St Michael in Oxford (no. 1), are of Taynton stone; they are in or near the Thames valley at locations reasonably accessible from the Taynton quarries.

Great Oolite Group, White Limestone Formation

In Oxford, St Aldate's 1 is of oolitic limestone with light yellowish ooliths of 0.3–0.4 mm diameter, close-set in a pale grey fine-grained matrix. Many of the ooliths project on a fractured surface of the stone, giving the rock a 'millet-seed' appearance. Fossils comprise an ostreid fragment and a number of small fragments of fossil wood. Though unusual in oolitic limestones, fossil wood does occur in oolites in the Forest Marble and White Limestone formations north of Oxford, deposited close to contemporary shorelines. The carving could well be of Bladon stone, a White Limestone oolite (Sumbler 1984), used for Oxford buildings since at least the fourteenth century (Arkell 1947).

The sundial from Marsh Baldon, Oxfordshire, is also of oolite of 'millet-seed' type, which may be from Bladon or elsewhere on the White Limestone outcrop near Oxford.

Bathonian, Calcaire de Caen Formation (Caen stone)

The Calcaire de Caen is of the same age (Bathonian) as the Combe Down Oolite, Taynton Stone and White Limestone, but is of different facies from any of them. Caen stone, familiar from its large-scale usage in Norman buildings, is a fine-grained, soft, yellowish (2.5Y 8/2) and more rarely whitish limestone. It is not oolitic, and its particles are barely resolvable under the hand lens. Its fineness of grain and poorly developed bedding indicate sheltered, perhaps lagoonal, conditions of deposition. Weathered surfaces of the stone may be pitted by small hollows of 10–20 mm diameter. Cavernous weathering of this type is commonly attributed to the activity of burrowing organisms in the sediment before lithification. According to Rioult, the Calcaire de Caen in the Caen vicinity has a thickness around 35 m, of which the lower 12 metres or so is marly and is not exposed in the quarries (Rioult 1962).

Mr R. W. Sanderson, of the Natural History Museum, described a thin section, seen under a microscope, of a small cored sample from a frieze or blind-arcade fragment in Sompting church (no. 9), as follows (in litt., November 1989):

'The stone is a fine-grained pelletal limestone. Small foraminifera are relatively abundant. Micritic fecal pellets, ovoid in shape and between 0.06–0.15 mm in length, are embedded in a patchy micritic paste of less dense appearance, together with abundant small shell fragments. Some irregular sparry grains of calcite enclose echinoid fragments in optical continuity. The stone compares well with that in a sequence of thin sections taken at 25 cm intervals through the La Maladrerie Quarry section, Caen, though bedding is more distinct in the Sompting stone than in that of the Caen quarry.'

Caen stone was used for one architectural feature at Winchester (an undecorated circular window (WS 198) not included in the present volume), and for a small Crucifixion panel at Romsey (no. 2). It is elsewhere represented along the south coast at Bosham, Sompting (where it is much in evidence), Botolphs, Jevington, and Dover (St Mary in Castro 1).

Bathonian, Oolithe de Marquise Formation (Marquise stone)

The importation of Marquise stone, from near Boulogne, into east Kent both by the Romans and in the early Norman period has only recently come to light (Worssam and Tatton-Brown 1990; Tatton-Brown 1990). Anglo-Saxon sculptures in this stone are the Reculver columns (no. 4), Canterbury St Martin 1, and baluster shafts from St Augustine' abbey, Canterbury (nos. 6 and 7).

The Reculver columns consist of a pale grey oolite of 'millet-seed' type, formed of close-packed grains (which may be pseudo-ooliths) of 0.2–0.5 mm diameter. Two varieties of the stone are seen in the columns: one is characterised by scattered, very coarse oncoliths (i.e. aggregates of ooliths enclosed in a thin outer coating), 2 mm in diameter; the other is a more even-grained oolite, without oncoliths. The St Martin's church inscription is on stone of the latter type.

The main outcrop of the Oolithe de Marquise measures only 10 km or so along the strike (Fig. 7). The formation has lithological points of resemblance to the White Limestone which, in the writer's opinion, could well pass laterally into it.

Ancholme Group, Corallian Beds

In the neighbourhood of Oxford the Corallian Formation includes the hard Coral Rag, used for rubble walling, and the Wheatley and Headington freestones, both of which are reef-apron deposits, composed of irregularly-sized sub-rounded detritus rather than of ooliths. Wheatley stone is recorded as having been used in Oxford from 1290 onwards, while Headington stone was brought in only after the end of the fourteenth century (Arkell 1947).

The tower of St Michael's church, Oxford, has Coral Rag walling, but some of its quoin stones are of a fine-grained limestone with conspicuous oyster-like shells, and are perhaps Wheatley stone with Exogyra nana, as recorded by Arkell in the front quadrangle of New College (Arkell 1947). One of the tower windows, that on its east side at the second stage, has a baluster shaft of similar shelly limestone.

There seems no warrant for Jope's identifications of carved stones in London (at All Hallows and Stepney) as Wheatley stone (Jope 1965, 109), for both are of oolitic limestone.

Portland Group, Portland Limestone Formation (Portland stone)

Portland stone, a near-white (5Y 8/1) oolite, quarried principally on the Isle of Portland, and the most widely used building stone of southern England from the seventeenth century onwards, is represented by only four small pieces of Anglo-Saxon carving. These, Winchester Old Minster nos. 38, 41, 42 and 74, are even-grained, with ooliths of 0.3–0.4 mm diameter, closely packed but with numerous interstitial voids — a texture quite different from that of Bath stone. Shell fragments are sparse.

Purbeck Group, Durlston Formation (Purbeck Marble)

The Purbeck Group comprises the Lulworth Formation, below, and the Durlston Formation, above. The Jurassic-Cretaceous boundary is at or near the boundary between the two formations. Purbeck Marble occurs near the top of the Durlston Formation, in the Isle of Purbeck (Melville and Freshney 1982, 62).

The 'marble', so much a feature of thirteenth-century English churches, was used for only two extant Anglo-Saxon sculptures in south-east England. One, a large grave-cover from the cathedral in Oxford, is of typical lithology, composed of small gastropod shells of the genus Viviparus, closely packed in a fine-grained matrix. The stone is 'blue-hearted', with pale greyish-brown top and bottom surfaces, these being more weathered. The other sculpture, a small fragment of carved drapery from Winchester Old Minster (no. 85), is of a rather unusual Purbeck Marble lithology, being composed of broken shell fragments, apparently mostly of bivalves.

Wealden Group, Hastings Beds division

The Wealden Group is a thick sequence of fresh- to brackish-water clays and sands. Its lower part, the Hastings Beds, occupies the central part of the Weald, and comprises three formations, from below upwards the Ashdown Beds, the Wadhurst Clay and the Tunbridge Wells Sand. Fine-grained yellow-brown Hastings Beds sandstone was used for sculptures at Bexhill, Sussex, and Rochester, Kent.

The Bexhill stone is composed of quartz grains of 0.1–0.2 mm diameter, in 1–2 mm laminae that show small-scale trough cross-bedding. The cross-cutting relationships of the bedding incidentally show that the stone, as carved, is geologically right-way up. Stone of this type could be matched in the Ashdown Beds or the Cliff End Sandstone (Wadhurst Clay Formation). Both crop out in the Hastings vicinity, and large blocks of sandstone litter the foreshore below sea cliffs in which the beds are exposed.

The grave-marker Rochester 3 is of very evenly graded fine-grained sandstone, with the rather friable 'sandrock' texture typical of Hastings Beds sandstones. The nearest outcrops of stone of this type are in the Medway valley upstream from Tonbridge. Alternatively the stone could have been shipped from Hastings.

Lower Greensand Group, Hythe Beds Formation (Kentish Rag)

Both Lower Greensand and Upper Greensand are characterised by the occurrence of grains of the green mineral glauconite; it indicates marine conditions of deposition. Kentish Rag, a sandy limestone occurring in the Hythe Beds in Kent, was used for the grave-cover from Dover St Peter, Kent, and for the cross-head from St John Walbrook, London.

The Dover cover is of dark grey glauconitic sandy limestone, with some well-rounded quartz grains of 2 mm diameter and glauconite grains up to 1 mm across. The back surface of the stone is not dressed, and shows a nautiloid cast 80 mm in diameter and a number of 10 mm-wide infilled burrows. Limestones of this type occur in the upper part of the Hythe Beds between Sellindge and Hythe (Fig. 7; Smart et al. 1966).

The St John Walbrook, London, cross-head is of a much finer-grained stone. Some dark grey inclusions of about 10 mm diameter suggest the phosphatic nodules that occur in some ragstone beds of the Maidstone area, whence ragstone was shipped into London in large quantities in Roman and medieval times.

Lower Greensand Group, Hythe Beds sandstones of Surrey and Sussex

Westward of Westerham, the Kentish Rag facies of the Hythe Beds is replaced by one of sands with beds of non-calcareous sandstone. The sandstone has been worked for building stone between Westerham and Limpsfield, and on the south side of the Weald between Petersfield and Pulborough. Four of the seven quarry localities in England recorded in the Domesday Book were on this sandstone. They were Limpsfield (two quarries), and, on the south side of the Weald, Grittenham, Iping, and Stedham (Darby 1977).

Grave-covers at Titsey, Oxted and Tandridge, in Surrey, are of a pale olive (5Y 6/3) to greenish brown sandstone, with quartz grains of 0.3 mm diameter, very fine (0.1 mm) glauconite grains, and some moulds of sponge spicules. The large size of these covers is noteworthy. Stone with a texture closely matching this was mined in the nineteenth century at Hosey Common, south of Westerham (Dines et al. 1969, 68).

Hythe Beds sandstone in west Sussex has been given various local names, of which Pulborough stone is one. It is, however, uncertain whether the stone differs markedly from one locality to another, and no particular local name seems appropriate for the stones described here. Grave-covers at Chithurst, Stedham, and Cocking in Sussex, are of pale yellow (5Y 8/2 to 2.5Y 8/4) stone of a similar grain size to that in Surrey. A cored sample from the Cocking cover includes moulds of sponge spicules. Some of the Chithurst and Stedham covers display round cavities of 10–20 mm diameter with a 2 mm-thick, hard limonitic lining. So does sandstone used for the nineteenth-century south porch of Stedham church, which points to a common source.

The capitals of mid-wall shafts of the two north belfry windows of Sompting church, Sussex (nos. 20–1) are of similar stone to that of these grave-covers. They have been in part repaired with a closely matching sandstone, identified by Dr Martyn Owen (in Aldsworth and Harris 1988, 117) as Pulborough stone.

The two grave-covers at Steyning, Sussex, are of a slightly finer-grained sandstone (0.2–0.3 mm quartz grains). A cored specimen of no. 2 is pale yellow (2.5Y 8/2) speckled dark green, shows sponge-spicule moulds, and is quite similar to stone marketed (in 1988) as Midhurst stone, from James's Quarry (Thurrell et al. 1968, p.77), about 3 km north of Midhurst. The carved window-head at Tangmere, Sussex, is of stone with a similar texture but an overall olive-grey colour.

Lower Greensand Group, Woburn Sands Formation

North of London the Lower Greensand is represented by the Woburn Sands, loose yellow sands with impersistent layers of ferruginous sandstone, known locally as carstone. The cross-shaft in Stanbridge churchyard, Bedfordshire, is of hard, dark reddish brown sandstone with sub-angular to well-rounded quartz grains of 0.5–0.9 mm diameter and sub-angular 0.3–0.4 mm opaque grains, close-packed in a dark brown limonitic cement. In all probability it came from this formation. Similar (though finer-grained) sandstone was used in the fifteenth century for the tower and clerestory of the church.

Gault Group, Upper Greensand Formation (Reigate stone)

The Upper Greensand of the Reigate vicinity provided great quantities of building stone for London and its surrounding area from the eleventh century onwards. Anglo-Saxon sculptures of this stone are found at Betchworth and Reigate in Surrey, and at Orpington and Dartford in Kent. The stone is a fine-grained sandstone, pale grey with a slight greenish tinge (5Y 7.5/1), and is composed of 0.1–0.2 mm granules which seem to be of authigenic (i.e. grown in-situ) silica rather than of detrital quartz. It is dusted with very fine (0.1 mm) glauconite, and commonly contains scattered mica flakes. All the more important workings for building stone seem to have been along a fifteen-kilometre stretch of the outcrop between Brockham, 5 km west of Reigate, and Godstone, to the east (Sowan 1976). Names such as Gatton stone and Merstham stone, ostensibly reflecting the source of the stone, have been used, but the stone from all localities is geologically indistinguishable, and the single name Reigate stone is now generally favoured.

Gault Group, Upper Greensand other than Reigate stone

A decorative fragment at Ford, Sussex, is of stone which, though closely similar to that described as from Reigate, could be 'malm rock' (Jukes-Browne 1900, 116) from the Sussex outcrop of the Upper Greensand. The Domesday Book recorded a quarry (for millstones) at Bignor, on the Upper Greensand not far from Ford (Darby 1977).

At outcrop on the coast at Eastbourne the Upper Greensand formation, some 10 metres thick, consists of sandstone that differs from Reigate stone in being composed of distinct quartz grains (0.2 mm diameter) and in containing more glauconite, giving it a greenish-grey colour. The baluster shafts of the belfry windows of Jevington church tower (no. 2) were fashioned from this stone, and some large blocks of it are included in the mainly flint-rubble walling of the tower.

Reid stated that the stone 'was formerly taken from the reefs between tide-marks, and used for building-purposes' (Reid 1898, 14). Indeed, much if not all of the Eastbourne stone used for building, from Roman times (for Pevensey Castle) onwards until the nineteenth century, must have come from the foreshore, for the outcrop extends only for 2 km or so inland from the coast, concealed throughout beneath Drift deposits.

A similar type of Upper Greensand to that at Jevington is represented in Hampshire at Whitchurch and Winchester (Prior's Barton 1). An inlier at Kingsclere is perhaps a possible source for the stone at Whitchurch. At Breamore, the inscribed voussoirs of the south porticus arch (no. 2c) are, according to Tim Tatton-Brown (pers. comm., 1994), of Hurdcot stone, a sandstone from an Upper Greensand outcrop at the east end of the Vale of Wardour, about 20 km north-west of Breamore, which was in use as a building stone before Chilmark stone began to be exploited for that purpose.

Chalk Group

At Winchester a carved block (Old Minster 64) of fine-grained grey limestone, of less than 0.1 mm grain size, apparently slightly silty and not glauconitic, may well be of Lower Chalk. There is a small inlier of Lower Chalk on the east side of the Itchen valley at Chilcombe, just east of Winchester. Other outcrops of it lie 20 km or more from the city.

At Walkern, Hertfordshire, a Crucifixion figure (no. 1) on the wall above the south nave arcade, though mounted too high for close examination, appears to be of white chalk. It may have been whitewashed. Walkern is on the Chalk outcrop, and the source of the chalk used for the sculpture need not have been distant. A limewashed or emulsion-painted impost at Walkern (no. 2) may also be of chalk, like that at Little Munden in Hertfordshire.

Thanet Beds Formation

From Roman times onwards much use was made of a fine-grained, light grey (5Y 7/1) calcareous sandstone from the Thanet Beds for rubble walling in east Kent. At St Augustine's abbey, Canterbury (in early Norman walls), many blocks of it have holes bored by, and containing the shells of, Recent bivalve molluscs (Tatton-Brown 1991, 86). These blocks must therefore have been collected from the foreshore below one of the two cliff sections where the sandstone crops out: between Herne Bay and Reculver; and at Pegwell Bay on the south side of the Isle of Thanet. The stone is poorly exposed inland, and in all likelihood most if not all of that used in building came from one or other of its foreshore localities.

Two sculptures in this stone are from Canterbury St Augustine's abbey. They are a grave-cover (no. 2) and a small carved stone (no. 10). The grave-cover, 102 cm long, 43 cm wide and 15 cm thick, is of pale greyish-brown sandstone composed of well-rounded 0.1–0.2 mm quartz grains, with numerous black glauconite grains of 0.1 mm diameter. The carved stone has slightly coarser quartz grains (0.2 mm, with some up to 0.3 mm); it shows traces of sponge spicules and a fine-grained, bluish-grey inclusion which may be of chert.

A third sculpture which may be of Thanet Beds sandstone is the grave-cover at Great Canfield church, Essex, reused as the south impost of the chancel arch. Its dimensions are close to those of the St Augustine's abbey cover. It contains quartz in well-rounded 0.2–0.3 mm grains and glauconite in grains mostly of 0.2 mm but some 0.1 mm in diameter. The edge of the cover shows glauconite grains concentrated along planes of small-scale cross-bedding. They also surround burrows, oval in cross-section owing probably to compaction of the sediment, 14–18 mm in width, and infilled with clear quartz grains. Similar-sized burrow casts are displayed by some sandstone blocks on the foreshore west of Reculver.

Calcaire Grossier Formation

The clays and sands of the Bracklesham Group in England are represented in the Paris Basin by a thick near-white (10YR 8/2) foraminiferal limestone, the Calcaire Grossier, quarried and mined for building stone since Roman times. Calcaire Grossier was identified by Dr L. R. Cox (in Peers 1927b) as the stone of the lost cross-head from Reculver (no. 3). It was next identified as a sculptural stone in this country by Mr Dennis Curry, who reported as follows on the Anglo-Saxon cross-head fragment in Pagham church, Sussex:

'The rock is a soft biocalcarenite, with a small proportion, (possibly 10%) of fine angular quartz sand. It has suffered notable diagenesis: it was originally rich in organic fragments, especially foraminiferids, most of which are now unidentifiable. The matrix was examined for nannoplankton but without success, owing no doubt to the diagenesis. The rock contains numerous tubes of the unattached Serpulid worm Ditrupa, no doubt strangulata (Deshayes). Aragonitic fossils have lost their shells, but the following can be identified from moulds: Venericardia, Pitar or Callista, Mesalia, and a cerithiid. Amongst the foraminifera are; Orbitolites (no doubt complanatus Lamarck), miliolids (Miliola saxorum d'Orbigny?), and species of Cibicides, Hanzawaia, Reussella, Bulimina, and Rotalia? In north-west Europe Orbitolites only occurs in the Lutetian, including Paris Basin zones III and IV of Abrard (Middle Lutetian of Pomerol) and Hampshire Basin, Upper Bracklesham Beds ... White or buff limestones occur in the Eocene of the Paris Basin, where they are known as Calcaire Grossier. They are also present near Arthon and Valognes, and sporadically in Belgium. Only those of the Paris Basin are regularly worked for building stone. Ditrupa occurs at levels throughout the north-west European Eocene, but very sporadically. I only know of one limestone level where it is both common and widespread. This is Zone III of Abrard: 'La Zone III est le plus souvent très riche en Ditrupa strangulata (Deshayes), ce qui lui a fait donner le nom de "calcaire à Ditrupes"' (Abrard 1925, 370). All the fossils here recorded are consistent with an ascription to the Middle Lutetian of Pomerol, and the lithology also matches well (Pomerol 1973). I therefore think the limestone must be 'mid-Lutetian', and that it came from the northern part of the Paris Basin, very probably from somewhere between Creil and Laon. None of the other areas here mentioned give a good lithological match, nor is Ditrupa conspicuous in any of them.' (Dennis Curry, in litt., January 1988).

The shaft fragments from Reculver, Kent (no. 1) are also of Ditrupa limestone, and these too have proved to be of Calcaire Grossier, of a bed known to quarrymen in the Oise valley as the Banc de St Leu (Worssam and Tatton-Brown 1990). Other east Kent sculptures in the same limestone are two grave-markers with runic inscriptions from Sandwich, three Composite capitals from St Augustine's abbey, Canterbury (nos. 3–5), and a column (Blagg 1981) in the church of St Pancras, Canterbury.

The stone for the Pagham cross-head may have come from the ruins of the first-century Fishbourne palace (Worssam and Tatton-Brown 1990), as also, possibly, did blocks of Ditrupa limestone built into the late Anglo-Saxon tower of Bosham church, Sussex (Aldsworth 1990).

Two Winchester column fragments are of Calcaire Grossier. One of them, Old Minster 12, is a Ditrupa limestone of Banc de St Leu type, with Orbitolites. The other, Old Minster 19, has small cavities that are the external moulds of cerithiid gastropods. Cerithium, adapted to flourish in conditions of variable salinity, is characteristic of the upper part of the Calcaire Grossier formation (Blondeau et al. 1980). Limestone of this type could have come from the upper levels of a quarry working the Ditrupa limestone.

Solent and Bembridge Formations (Headon Hill limestone, Bembridge limestone and Quarr stone)

The Bembridge Formation (Melville and Freshney 1982, 108) is restricted to the Isle of Wight, and comprises the Bembridge Limestone, below, and the Bembridge Marls, above. The Bembridge Limestone, 5.5 metres thick in the west of the island and 8 metres thick in the east, contains massive beds of fine-grained limestone that include freshwater gastropods and moulds of nucules of the water plant Chara. The latter are calcite-lined hollow spheres of about 1–2 mm diameter; under the hand-lens their walls show a spiral ornament.

Quarr stone represents a local facies of the Bembridge Limestone, formed from closely packed gastropod shell fragments. Anderson and Quirk suggested that the stone originated as a roughly elliptical bank of shell detritus at an early stage in deposition of the Bembridge Formation (Anderson and Quirk 1964). The stone was quarried at Quarr, in the north-east of the island, from Roman times until becoming virtually exhausted by the beginning of the fourteenth century. Quarr stone is easy to recognise. It is pale grey (10YR 7/1) to yellowish (2.5Y 8/2). Initially a felted mass of small arcuate shell fragments, around 3–5 mm long and 0.2 mm thick, these have been dissolved out to leave arcuate voids in a matrix of crystalline calcite. A lithology transitional to the fine-grained type of Bembridge limestone can occur, in which the shell fragments, distributed in clusters, themselves occur as crystalline calcite. The sundial from Bishopstone, Sussex is considered to be an example of this.

Anderson and Quirk proposed the names Binstead Stone and Quarr Stone for the normal and detrital-shelly parts of the Bembridge Limestone respectively (Anderson and Quirk 1964). Neither term has been taken up by subsequent geological authors. The name Bembridge limestone (with a small 'l') is used here to indicate fine-grained limestone from the Bembridge Formation, irrespective of where on the outcrop it may have been quarried.

Bembridge limestone, so defined, was used for a grave-cover from the excavations at Winchester Old Minster (no. 6) and its associated foot-stone (no. 2). The most easterly Anglo-Saxon occurrence of the limestone is a grave-marker from Arundel, Sussex. It is almost completely lichen-covered, but has closely-spaced 1 mm-diameter perforations, which are taken to be Chara nucule moulds. Some Bembridge limestone blocks, for instance the cross-base from South Hayling, Hampshire, show irregular small solution-cavities, which may have been initiated at the hollow moulds of gastropod shells.

Two fragments from Selsey (nos. 2 and 3), are of typical Bembridge limestone appearance, containing Chara nucules and moulds of smooth-shelled gastropods; nos. 1 and 4 from that site are of fine- to medium-grained pelletal limestone with fine shell detritus. Mr D. Curry, on examining the Selsey fragments, mentioned the possibility (personal communication, 1988) that these (and, presumably, others among the carvings classed as Bembridge limestone) could be from the Headon Hill Limestone in the western part of the Isle of Wight, a 4.3 metre bed at a lower horizon (Solent Formation) than the Bembridge Formation, but which also includes Chara nucules.

Stones of Uncertain Provenance

In Hampshire, three limestone sculptures, those at Steventon, Wherwell, and Bishop's Waltham, are planar-bedded shell-detrital oolites, with ooliths around 0.3 mm in diameter. Though from 70–100 cm long, none of the blocks show the calcite veinlets that normally serve to indicate Bath stone. The carvings from Winchester Upper Brook Street and High Street are coarser-grained, with 0.4–0.5 mm ooliths.

A carving from the Old Minster at Winchester (no. 5) is of greyish-yellow oolitic limestone with fine-grained (0.2 mm) ooliths in a calcite matrix which also includes unevenly scattered larger ooliths or ovoid pellets, mostly of 0.5–0.8 mm diameter. There are occasional whole fossil shells, notably a hollow bivalve or brachiopod cast with calcite lining. The stone is probably from the Great Oolite Group of the Bath-Cotswolds region.

At Langford, Oxfordshire, the sundial high up on the south face of the church tower (no. 3) appears to be of limestone, with signs of cavernous weathering and of shells that may be ostreids. If they are, this might possibly be a Corallian limestone from near Oxford; a Cotswold Inferior Oolite source is perhaps less likely.

At West Wittering, Sussex, a small triangular stone with inscribed crosses appears to be of 'millet-seed' oolite, but is far from any Jurassic outcrop and has no obvious source.

A fragment from Rochester, Kent (no. 1) is of pale brownish yellow, slightly shelly oolitic limestone, unevenly graded, with a few 1 mm pale orange limonitic grains and some sub-rounded 1 to 2 mm pellets or oncoliths. It resembles to some extent the stone of a slab from St Augustine's abbey, Canterbury (no. 9), which also includes limonitic pellets and may be an 'ironshot' variety of Bath stone.

Carved fragments at Little Somborne, Hampshire, are of a porous limestone, of which little can be seen beneath their limewash coating. The stone, if not Bembridge limestone, may possibly be a geologically Recent calcareous tufa, extensive deposits of which occur in the flood plain of the River Test near Stockbridge, only 3 km north-west of Little Somborne (White 1912).

Two carvings from London, a cross-head fragment (All Hallows 2), and a grave-cover (City 1), are of pale grey to brownish, even-grained, fine, porous sandstone of 0.1–0.2 mm quartz grains, with a few dark grains which may or may not be of glauconite. The grain size is that of Hastings Beds sandstones, and it is difficult to suggest any other source of such large blocks reasonably close to London.