Spreadsheet: 11849d06-1d95-4e5b-8b50-451c69717890
Sheet: Stones

BUILDING_STONE_ID | STONE_NAME | PARENT BUILDING STONE  ID | ALTERNATIVE_NAMES | [NAME] | COLOUR | COLOUR_VARIATION | WEATHERED COLOUR | LITHOSTRATIGRAPHY | CHRONOSTRAT | STONE_LITHOLOGY | GRAIN_SIZE | [NAME] | KEY_IDENTIFICATION_FEATURES | FAILURE_WEATHERING | CONTEXT_OF_USE | LOCALITY_OF_USE | DATE_COMPILED | COMPILED_BY | MINERAL PLANNING AREA | English Heritage Atlas Area | SOURCE_OF_INFO | retrieval_date
4101 | Sandrock | 1 | Godrevy Sands and Gravel | One of the geologically youngest building stones to be used in Britain, probably having been deposited as a raised beach during the last interglacial period, about 150,000 years ago. Thickness 2- 4 m at Godrevy. | YELLOW | Uniform | Weathers pale yellowish. | BEACH DEPOSITS | [NAME] | SANDSTONE | Medium grained | High shell content of the beach sand ensured sufficient calcium carbonate was available in saturated pore waters to precipitate as a prevasive cement. | Pale yellow, calcite-cemented, shelly beach sands, with a high bioclastic content (60%). Grain size varies from medium to coarse. Formed as part of raised beach. | Only just about hard enough to be used as a bulding stone. Crantock church tower collapsed  shortly after  it was built in the 14th Century, indicating structural limitations with sandrock. | Used very locally, mainly for older churches at Padstow and Crantock. Also for internal use, for example, font at St Enadoc. | Beach sands on the north coast, Godrevy Point near Hayle, in the Padstow Estuary and the north side of Fistral Bay. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1975; Selwood, Durrance & Bristow, 1999; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4102 | [NAME] | 1 |  |  |  | Uniform |  | CORNBRASH FORMATION | CARBONIFEROUS | GRANITE |  |  |  |  | ? | Cornwall | 2010-05-11 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | ? | 2012-05-16 10:20:32
4104 | Land's End Granite | 4102 |  | Local gradation between megacrystic and poorly megacrystic granite varieties occurs within the Land's End granites. For example, at Porthcurno (SW 392 224), a gently inclined sheet of fine-grained granite, 100m thick, grades through various intermediate types, and then imperceptibly into underlying coarse, megacrystic granite. | GREY | Uniform | Variable, but often darker. | LAND'S END INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | May comprise two separate intrusions and be of more complex origin, similar to the St Austell granite: the Zennor lone (the northeastern part of the granite mass); and [NAME] lobe (southern intrusion). | A leucocratic to mesocratic, entirely biotite-mica granite. The dominant granite  type is coarsely to very coarsely-grained, with feldspar megacrysts up to 20 cm in length, which often exhibit an interlocking, non flow-orientated, pattern.  (Only the St Austell granite, [NAME] type, exhibits similar sized megacrysts, this contrasts with megacrysts in the Carnmenellis and Bodmin Moor plutons, which reach an average length of 20mm). Within the Land's End granites, coarse-grained varieties are characteristic of the Castallack and Lamorna areas; finer-grained granites (also megacryst-rich) occur in the Castle-an-Dinas area. | Very hard, resistant, durable. | Used throughout the Land's End area as building stone, and for other structures (eg. [NAME] walls). The main quarries were at Lamorna, Sheffield, Castallack and Castle-an-Dinas. [NAME], on the southern side of Land's End granite, formerly produced high-quality dimension stone which was used locally and exported from a small harbour in the cove.  Granite from here was used for the Embankment in London, Mousehole pier and [NAME] lighthouse. | Land's End Peninsula,south west Cornwall, encompassing much of Penwith District, extending approximately from [NAME], via Porthcurno, Land's End, Zennor to near St Ives. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Flett, 1907; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Booth & Exley, 1987; Goode  & Taylor, 1988; Bristow, 2001 | 2012-05-16 10:20:32
4105 | [NAME] Mount Granite | 4102 |  | Wave-cut granite platforms on the south side of the Mount expose a stockwork of east-west greisen-bordered veins with cassiterite, wolframite, stannite and copper mineralisation. | PALE-GREY | Uniform | Variable, but often darker grey. Often covered with marine weeds, algae etc. | ST [NAME] MOUNT INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | Sheeted-vein systems (swarms of mineralised veins) occur on the southern side of the Mount. | A small granite cusp projecting up offshore in Mount's Bay. near Penzance. The main granite is a mesocratic, coarse-grained biotite-mica granite, containing small feldspar megacrysts. | Very hard, resistant, durable. | Very localised use as a building stone on [NAME] Mount. | [NAME] Mount, near Penzance. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Goode & Taylor, 1988; Bristow, 2004 | 2012-05-16 10:20:32
4106 | Tregonning Granite | 4102 | Tregonning-Godolphin Granite | Exposures in the cliffs near Megilligar Rocks show spectacular very coarse grained pegmatite-aplite-granite sheets cutting metamorphosed slates in the roof zone of the intrusion. | PALE-GREY | Uniform | Variable, pale [NAME] to darker greyish. | TREGONNING INTRUSION | PERMIAN to PERMIAN | GRANITE, MEDIUM-GRAINED | Medium grained |  | A leucocratic, pale-coloured, medium-grained granite. Non megacrystic, and one of the two Cornish granites (the other is [NAME] stone, part of the St Austell granite intrusion) to contain lithium-mica and zircon. The lithium-mica can often be distinguised by its pale brown or pale mauve colour (biotite is typically much darker) and presence of topaz.. | Very hard, resistant, durable. | Used mainly in the Tregonning - Godolphin area as local buildling stone. | Tregonning-Godolphin, west Cornwall. Extends southwards from Tregonning Hill (SW 600 300) to coastal exposures between [NAME] and [NAME] (SW 607 257). | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Stone, 1975; Taylor & Wilson 1975; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4107 | Godolphin Granite | 4102 | Tregonning-Godolphin Granite |  | PALE-GREY | Uniform | Variable, but often darker. | GODOLPHIN INTRUSION | PERMIAN to PERMIAN | GRANITE, FINE-GRAINED | Fine grained |  | A distinct, leucocratic to mesocratic, fine-grained variety of biotite granite, containing small K-feldspar megacrysts. | Very hard, resistant, durable. | Used mainly in the Tregonning - Godolphin area as local buildling stone. | Tregonning-Godolphin, west Cornwall. Extends southwards from Godolphin Hill (SW 593 313) to vicinity of [NAME] and Wheal Fancy. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Stone, 1975; Taylor & Wilson 1975; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4108 | [NAME] | 4102 |  | The largest block of granite ever extracted in SW England came from [NAME], weighing in at a claimed 2738 tonnes. | PALE-GREY | Uniform | Variable, but often darker. | CARNMENELLIS INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | The Carnmenellis granite sometimes shows a preferred orientation of the constituent minerals (foliation) giving it a gneiss-like appearance. The most intense zone of tin and copper mineralisation in the whole of the Cornubian orefield lies on the northern flanks of the Carnmenellis granite. | A leucocratic to mesocratic, biotite mica granite, often rich in feldspar megacrysts, averaging approximately 20mm in length. Biotite mainly occurs as aggregated 'clumps'. A medium granite variant of the Carnmenellis granite occurs within the central of the pluton, and may represent a separate later intrusive phase. This variant is typically is megacryst poor, and biotite tends to occur as isolated grains. | Very hard, resistant, durable. | Granite has been extensively quarried in the south eastern part of the Carnmenellis granite, notably in the parish of [NAME], and formerly used as building stone. [NAME] provided the stone for the exterior of Truro Cathedral, and [NAME] was used to construct [NAME], Falmouth and St Mawes Castle. | A circular granite outcrop, approximately 12 km wide, centered on Carnmenellis, encompassing the area between Praze and Brill. Two smaller granite areas adjoin the main outcrop: [NAME] (south of [NAME]) and Carn Marth (north of the main [NAME] intrusion). | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1934; Al-Turki & Stone, 1978; Dangerfield & Hawkes, 1981; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4109 | [NAME] | 4108 |  |  | PALE-GREY | Uniform | Variable, but often darker. | CARNMENELLIS INTRUSION | PERMIAN to PERMIAN | GRANITE, FINE-GRAINED | Fine grained |  | A leucocratic, fine grained variety of Carnmenellis granite, poor in feldspar megacrysts. Occurs only in small outcrops at Boswyn and Praze. It's relationships to the other coarse- and medium-grained granites within the Carnmenellis granite are unclear | Very hard, resistant, durable. | Locally used as a general building stone. | Two small granite outcrops on the western edge of the Carnmenellis granite, at Praze and Boswyn. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1934; Al-Turki & Stone, 1978 | 2012-05-16 10:20:32
4110 | St Agnes Beacon Granite | 4102 |  | Together with [NAME] granite, the St Agnes Beacon granite forms a small cusp on a northerly projection of the Cornubian batholith. | PALE-BUFF | Uniform | Variable, from pale to dark, partly dependant on mineralisation. | ST AGNES INTRUSION | PERMIAN to PERMIAN | GRANITE, FINE-GRAINED | Fine grained | Greisenised, and mineralisation of cavities. | Leucocratic, fine-grained granite, in places megacrystic (and coarse-grained), but characteristically intensely greisenised and mineralised. Most of the feldspar has either been replaced by secondary mica or quartz, or dissolved to leave cavities which were subsequently mineralised by cassiterite, wolframite and other metalliferous sulphides. In some varieties, the amount of quartz present is relatively low in comparison with other granites. In contrast, tourmaline is often abundant, and forms a speckled appearance (with quartz and muscovite mica) in the groundmass. Biotite is present, but either colourless or pale brown. Unlike [NAME] granite, St Agnes Granite exhibits little kaolinisation, largely because the feldspar was already altered to mica or quartz. | Fairly hard, resistant, durable. | The altered granite on the west of St Agnes Beacon has been used as a facing stone for some on the buildings in the village. Limited outcrop and difficulty of dressing prohibited wider use. The only surface exposure of the St Agnes granite is at Cameron Quarry, SW 704 506. | A small granite outcrop, 500 x 200 m, just west of St Agnes Beacon, near St Agnes, SW of Perranporth. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Sykes, 1993; Bristow, 2004 | 2012-05-16 10:20:32
4111 | [NAME] | 4102 |  | A larger granite outcrop than the St Agnes Granite, although the western half of the intrusion has been eroded away and lies under the sea. | PALE-BUFF | Uniform | Variable, from pale to dark, partly dependant on mineralisation. | [NAME] INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | A greisen bordered, sheeted-vein system. | A leucocratic, coarse-grained and poorly megacrystic granite, which like the St Agnes Granite has been greisienised and mineralised, but also exhibits greisen-borded sheeted-veins (absent at St Agnes). Zones of extreme kaolinisation also occur. In hand specimen, biotite is considerably bleached, and has a bronze colour, some mica is lithium rich. Microcline-perthite feldspar adopts a distinct pinkish or orangish colour. Mineralisation includes cassiterite and wolframite. | Fairly hard, resistant, durable. | Used previously in local area for facing buildings and as gate posts. Somewhat limited use due to difficulties of access to the cliff at Cligga Head - the only location where the stone is exposed. | [NAME], 2km west of Perranporth. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Sykes, 1993; Bristow, 2004 | 2012-05-16 10:20:32
4112 | St Austell Granite | 4102 | [NAME] | An attractive and striking variety of [NAME] is [NAME], which consists of black tourmaline and pink orthoclase feldspar, with some biotite; samples from Tregarden quarry also contain pyrite. It was mainly cut and polished for interior work (eg. walls of Porphyry Hall, Fowey). Another variety called 'Quartz schorl' (composed mainly of quartz and tourmaline) occurs in a craggy outcrop at Roche Rock (SW 991 596); the old ruined chapel atop the rock is built of Quartz schorl. | PALE-GREY | Uniform | Variable, but often becoming darker, lichen growth etc. | ST AUSTELL INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained |  | A leucocratic to mesocratic, coarse-grained biotite granite, containing large megacrysts of white orthoclase feldspar. The only other Cornish granite to exhibit large megacrysts of this type is the Land's End granite. This contrasts with megacrysts in the Carnmenellis and Bodmin Moor granite plutons, which reach an average length of 20mm. | Very hard, resistant, durable. | Used extensively as a building stone within Cornwall and beyond, and many famous buildings such as the British Museum, Old London bridge and Plymouth Breakwater, were constructed from it. High quality [NAME] was formerly extensively quarried from the Luxulyan area (including Tregarden, Carbean, Colcerrow and Orchard quarries). Within [NAME], examples of buildings using [NAME] include the exterior Porphyry Hall and the Tower at Place, [NAME]. It was also used in the construction of the Treffry Viaduct, the first large viaduct to be built in Cornwall. | Eastern part of St Austell granite, extending east of a line approximatelt from Bugle to just north of Carclaze, and extending east beyond Luxulyan. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Styles, 1993; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4113 | [NAME] | 4112 |  | An attractive and striking variety of [NAME] is [NAME], which consists of black tourmaline and pink orthoclase feldspar, with some biotite; samples from Tregarden quarry also contain pyrite. It was mainly cut and polished for interior work (eg. walls of Porphyry Hall, Fowey). Another variety called 'Quartz schorl' (composed mainly of quartz and tourmaline) occurs in a craggy outcrop at Roche Rock (SW 991 596); the old ruined chapel atop the rock is built of Quartz schorl. | PALE-GREY | Uniform | Variable, but often becoming darker, lichen growth etc. | ST AUSTELL INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained |  | A leucocratic to mesocratic, coarse-grained biotite granite, containing large megacrysts of white orthoclase feldspar. The only other Cornish granite to exhibit large megacrysts of this type is the Land's End granite. This contrasts with megacrysts in the Carnmenellis and Bodmin Moor granite plutons, which reach an average length of 20mm. | Very hard, resistant, durable. | Used extensively as a building stone within Cornwall and beyond, and many famous buildings such as the British Museum, Old London bridge and Plymouth Breakwater, were constructed from it. High quality [NAME] was formerly extensively quarried from the Luxulyan area (including Tregarden, Carbean, Colcerrow and Orchard quarries). Within [NAME], examples of buildings using [NAME] include the exterior Porphyry Hall and the Tower at Place, [NAME]. It was also used in the construction of the Treffry Viaduct, the first large viaduct to be built in Cornwall. | Eastern part of St Austell granite, extending east of a line approximatelt from Bugle to just north of Carclaze, and extending east beyond Luxulyan. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Styles, 1993; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4114 | [NAME] | 4112 |  |  | PALE-GREY | Uniform | Variable, but often becoming darker, lichen growth etc. | ST AUSTELL INTRUSION | PERMIAN to PERMIAN | GRANITE, MEDIUM-GRAINED | Medium grained |  | In composition, [NAME] granite is intermediate between the biotite-mica Luxulyan-type granites (from the eastern part of the St Austell intrusion) and the lithium-mica granites ([NAME] Stone) in the western part of the  intrusion. [NAME] granite is medium to coarse-grained and poorly megacrystic, the feldspar megacrysts reaching up to 40mm in length. Quartz occurs in rounded aggregate grains. Tourmaline and pale coloured biotite are also present within the Carn Grey granite, these typically occur in greater and lesser amounts (respectively) than in typical [NAME]. | Very hard, resistant, durable. | the fine, even-grained [NAME] granite was typically reserved for higher graded building work, and is the main stone used in older buildings of [NAME], eg. the Market House. | South central part of the St Austell granite, around Carn Grey tor (SX 033 551). | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Styles, 1993; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4115 | [NAME] Stone | 4112 |  | Non megacrystic lithium-mica granites from Tregargus Quarries (1 km NW of St Stephen) contain fluorite and zircon, and locally are known as 'shellstone' or 'chinastone'. | PALE-WHITE | Uniform | Variable, but often becoming darker, lichen growth etc. | ST AUSTELL INTRUSION | PERMIAN to PERMIAN | GRANITE, MEDIUM-GRAINED | Medium grained |  | Leucocratic, fine- to medium grained granites, containing lithium mica. Characteristically, these granites are the palest coloured granites in Cornwall, some varieties are almost white. They are non porphyritic, and comparatively fine-grained. | Fairly hard, resistant, durable. Slightly softer than most other granites, and easier to work. | Used locally and wider within [NAME] as a building stone. [NAME] church tower (near St Austell) and some of the older houses in Lemon Street, Truro are constructed of St Stephens Stone. St Pauls church, Charlestown, used lithium-mica granite from a quarry between [NAME] and Stenalees, which uniquely contains the mineral turquoise. | Western part of St Austell granite, mainly around Nanpean and Tregargus (SW 949 541), and an isolated outcrop further east at Hensbarrow. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Hawkes & Dangerfield, 1978; Dangerfield & Hawkes, 1981; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4116 | Bodmin Moor Granite | 4102 |  | [NAME] grained varieties (megacryst poor) occur in small outcrops SW and NE of the A30 road near Bolventor, and along the northern and southern margins of the Bodmin mass. | PALE-GREY | Uniform | Variable, but often becoming darker, lichen growth etc. | BODMIN INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | Flow banding, and phenocryst orientation occurs. Foliation and recrystallisation textures are associated with granites occuring on the western margins of the outcrop due to tectonic activity along the Portnadler-St Teath fault. | A leucocratic, coarse-grained biotite mica granite, mainly with small megacrysts (1-5% feldspar megacrysts) although gradations into megacrystic rich (5-9% feldpsar megacrysts) occur locally. Large megacrystic varieties also occur. Typically within the Bodmin Moor granite, the small megacrysts are 10-20mm long and composed of orthoclase microperthite, the groundmass comprises quartz and K-feldspars including microcline. Amongst the dark ferromagnesian minerals, biotite is present and also some tourmaline (1%).  The small megacrystic form characteristic of Bodmin Moor granite is characteristic, and is only really encountered in forms of the Carnmenellis granite and Isle of Scilly granites. | Very hard, resistant, durable. | Bodmin granite is widely used in Cornwall - especially the Bodmin area, and outside the county. Excellent quality, non-porphyritic medium-grained granite is worked in De Lank Quarry (western Bodmin Moor), and has been used in many famous lighthouses (Eddystone, Bishop Rock, [NAME]), bridges (Tower, Blackfriars in London) and Burlington House, Piccadilly. On the southeast side of Bodmin Moor, a large quarry below the Cheesewring also supplied high quality granite, which was taken for shipment at Looe via the Caradon railway. Several other quarries also operated in the same area. | Bodmin Moor, north central Cornwall | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1927; Hawkes & Dangerfield 1978; Dangerfield & Hawkes, 1981; Floyd, Exley & Styles, 1993; [NAME], 1996; Bristow, 2001; Bristow, 2004; | 2012-05-16 10:20:32
4117 | Elvan | 1 |  | Where a suitable elvan occurs, it is often quarried along its length, producing afeature like a railway cutting. For example, an elvan which runs from Davidstow Woods to Rock on the Camel estuary, was extensively quarried along its length (eg. near [NAME], SX 014 768) and used for the construction  of railway bridges between [NAME] and Wadebridge. | PALE-YELLOW | Uniform | Variable, but often becoming darkish yellow, or [NAME]. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | Variable. Porphyritic and non-porphyritic types occur; some displaying distinct flow lamination and chilled margins to the intrusion edges. | The felsitic elvans are amongst [NAME]'s finest building stones, some are true freestones and can be intricately carved. They are typically pale coloured and have a similar composition to granites, but are much finer-grained. They can be porphyritic (with phenocrysts of feldspar and/or quartz), or non-porphyritic. Some may be greisenised (development of mica) or kaolinised (replacement of feldspar) - the former is generally regarded to improve the quality of the stone for building purposes, the latter may render the stone softer. Tourmalinisation and reddening due to impregnation with iron oxides produces some attractive varieties. Elvans usually occur in the form of a dyke, between 2 - 10 m wide, and may extend across country for several miles. | Often fairly hard to very hard, durable building stones. | Worked in many parts of Cornwall, and widely used as building stones, often within close proximity to original quarries. Some elvan stones such as Tremore, Newham, and Pentewan are highly distinctive and well known, and have been extensively used for prestigious buildings or terraces within, and occasionally out of, [NAME]. | Formerly qarried at many locations throughout Cornwall. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906; Reid, Barrows & Dewey, 1910; Selwood, Durrance & Bristow, 1999; Bristow, 2001; [NAME], 2001; Bristow, 2004 | 2012-05-16 10:20:32
4118 | Pentewan Stone | 4117 | Elvan | Quarried since medieval times (cliff top quarries at Polrudden), most of the extraction in the 18th and 19th centuries occured at Pentewan. | PALE-YELLOW | Uniform | Darkish yellow, often becoming stained dark on exposed surfaces (eg. carved figures on St Austell church tower). | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | Non porphyritic, very even-grained texture. | Golden-yellow, [NAME] to pale straw coloured, non-porphyritic elvan, often tinged pink. Composed almost of quartz and mica, indicating the rock has been greisenised (with conversion of feldspar to quartz and mica). | Hard, durable stone, resistent to rainwater. Prolonged exposure to weather, over many centuries, can lead to the surface layer of the stone developing a honeycomb texture (eg. [NAME] church tower). | One of the most famous elvans used as building stone, and one of Cornwall's few freestones. Used widely within the Pentewan and [NAME] areas and beyond, including Pentewan church, [NAME] church tower, Torpoint (Antony House), St Mawes Castle, Charlestown, Bodmin (St Petroc) and Place, [NAME]. | Exposed in cliffs at Polrudden Cove (SX 026 475), north east of Pentewan (between [NAME] and Mevagissey); the elvan can be traced inland for 0.5 miles to Pentewan village (SX 022 478). | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher et al, 1909; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4119 | Pentewan-type Stone | 4117 | Elvan | Elvans from the St Austell area often show some degree of kaolinisation affecting the feldspars. | PALE-YELLOW | Uniform | Variable, but often becoming darkish yellow, or [NAME]. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | Variable, includes porphyritic types, and also stones with a range of grain size. | Several pale yellow or creamish coloured felsite elvans in this area have been used as local building stone,  and are conveniently referred to as 'Pentewan-type' Stone. The source quarries for these stones have long been infilled, and scant detailsabout them were available even to [NAME] (1909). Some varieties superficially resemble true Pentewan Stone in terms of colour, but can be distinguished as they contain feldspar phenocrysts - such as the elvan at Penrice Woods (SX 023 505) used to construct St Levan's church at Porthpean. One very fine-grained, whitish variant (used in the Georgian Penrice House) is thought to have come from infilled quarries near [NAME] (SX 027 498). | Fairly hard, durable resistant. | Several elvans of 'Pentewan-type' stone have been used as local building stones in the area south of [NAME], particularly around Polgooth, Sticker, Penrice, [NAME] etc. | Various elvans in the Polgooth, Sticker, Penrice and Porthpean areas, just south of [NAME]. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher 1909; Bristow, 2001; Bristow 2004 | 2012-05-16 10:20:32
4120 | Elvan - Warleggan | 4117 | Elvan | Most of the medieval buildings used local 'moorstone', but a quarry in the elvan was opened later (SX 152 697). | PALE-BUFF | Uniform | Similar to Pentewan Stone. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained |  | Porphyritic felsic elvan with common phenocrysts of feldspar and quartz, and occasional tourmaline and fluorite. Sill-like intrusion. Approximately 40% alkali feldspar, not greisened. Distinguished from Pentewan Stone by presence of quartz and feldspar phenocrysts. | Fairly hard, resistant. Lack of greisining may indicate this elvan is not as durable as Pentewan Stone. | Used as a local building stone In Warleggan area, including [NAME] church. | Warleggan and immediately vicinity, east of Bodmin | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1911; Bristow, 2001 | 2012-05-16 10:20:32
4121 | Elvan - St Agnes | 4117 | Elvan | Elvan width approximately 5 m. | GREY | Uniform | [NAME]. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | At its inland exposures, the elvan displays distinctive flow lamination at its margins, and is only porphyritic at its edges, the centre being evenly-grained, resembling a very fine microgranite. | Dull grey coloured, quartz feldspar porphyry, the quartz usually occuring as small blebs, the feldspar phenocrysts nearly 2 cm long, often kaolinised. Tourmaline is often abundant, bluish coloured, and occurs in small crystal 'rosettes'. At Wheal Prudence, the elvan has been silicified, and the feldspar largely removed; the groundmass here consists entirely of granular quartz and [NAME] with patches of limonite derived from pyrites. | Hard, durable, resistant. | Used as a local building stone along the elvan strike, quarried particularly at Wheal Prudence (by the old engine house), and at a large cliff-edge quarry at St Agnes Beacon. | From cliffs at St Agnes Head, via [NAME] to Wheal Prudence and Hanover Cove (near Perranporth). Inland the elvan strikes through old railway cuttings at Perran Combe and [NAME]. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906 | 2012-05-16 10:20:32
4122 | Elvan - Perranporth | 4117 | Elvan | Elvan width approximately 14 m near Hendra. Runs approximately parallel to St Agnes elvan. | PALE-GREY | Uniform | Grey to dark grey. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained |  | Very homogeneous elvan, with characteristics of a fine-grained granite. The orthoclase is white and sometimes porphyritic (but not markedly so), the quartz lacks distinct crystal boundaries and biotite appears fresh. Minor tourmaline is also present. The typical fine-grained, quartz-porphyry elvan appearance is only encountered towards the dyke edges. | Hard, durable, resistant. | Used as a local building stone along the elvan strike. Quarried at Perran Sands, near [NAME], [NAME], and Hendra farm. | From [NAME] (Perranporth), east of Ponsmere bridge, then east via [NAME], Rose village, Wheal Hope valley to near Hendra. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906 | 2012-05-16 10:20:32
4123 | Elvan - St Colomb Minor | 4117 | Elvan | Occurs in a 10 m wide dyke, which is tracable to the cliffs at Watergate Bay, but here it is rather decayed, and softer. At [NAME] the dyke has conspicuous chilled margins of finer-grained elvan, exhibiting a micropoikilitic groundmass. | PALE-PINK | Uniform | Similar to Pentewan Stone. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | Central part of the elvan exhibits a granophyric texture, with a micropegmatitic groundmass - an uncommon feature in Cornish elvans. Irregular jointing places limits on the size of stone blocks that can be quarried from this elvan. | A quartz-feldspar porphyry, with pink orthoclase set in a microgranitic matrix. In addition to the usual phenocrysts of perthitic orthoclase and corroded quartz, there is a significant amount of muscovite, and some biotite (indicative of greisenisation). The muscovite occurs as clusters and tuft-like aggregates rather than well-shaped crystals. Minor minerals include apatite, zircon and iron oxides. | Fairly hard, durable, resistant at St Columb Minor. | Used as a local building stone in St Columb Minor and vicinity (Trerice). Also used quite extensively in Newquay. | [NAME], near Newquay. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Reid & Scrivenor, 1906 | 2012-05-16 10:20:32
4124 | [NAME] | 4117 | Elvan |  | PALE-YELLOW | Uniform | Similar to Pentewan Stone. | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | Typically foliated. | A pale cream to pale yellow felsitic elvan, similar to Pentewan Stone, but often foliated and containing quartz veins. On casual examination it can superficially resemble a siltstone from the Portscatho Formation. | Fairly hard and durable. Does not carve as well as Pentewan type stone. | Used extensively in 18th and 19th Century buildings and terraces in Truro, in particular Lemon Street (which owes much of its character to this stone), the Royal Hotel and part of the 16th Century St Mary's church (now incorporated into Truro cathedral). | [NAME] at Newham (SW 830 437), 1 km south of Truro. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Bristow, 2001; [NAME], 2001; Bristow, 2004 | 2012-05-16 10:20:32
4125 | Tremore Porphyry | 4117 | Elvan | Quarried extensively at Tremorebridge (SX 010 648). [NAME] and Prince [NAME] so admired the stone on a visit to Cornwall in 1846, that they used polished slabs in alcoves in Osborne House, on the Isle of Wight. | RED | Uniform |  | UNNAMED DYKE, PERMIAN | PERMIAN to PERMIAN | IGNEOUS, FINE-GRAINED | Fine grained | The Tremore elvans are unusual in exhibiting alteration (tourmalinisation) of the rock. This is characterised by blue or blackish fine needles of tourmaline arranged in star-shaped bundles replacing the quartz/ feldspar ground mass. | An attractive elvan, with prominent large phenocrysts of white to pale pink orthoclase feldspar and quartz set in a red or pink fine-grained feldspathic matrix, with spherulitic growths of black tourmaline (schorl). | Hard, durable, resistant. | Used locally as both a decorative stone and building stone. Also used further afield, eg. [NAME], [NAME]. Also quarried by [NAME] in the 1830s to provide stone for polished slabs to line the spectacular Porphyry Hall in Place, [NAME]. | Tremore, near Withiel, west of Bodmin. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4126 | Kingsand Rhyolite | 1 | [NAME] | [NAME] up to approximately 100 m thick, interbedded conglomerates 8 m thick. Red colour of rhyolites is due to oxidative weathering. | RED | Banded | Often darkish red colour but variable, darker purple, brownish to greyish. | KINGSAND RHYOLITIC [NAME] | PERMIAN to PERMIAN | LAVA | Very fine grained | Rhyolites exhibit banding defined by alternating phyric and aphyric units. | Red-brown to purplish pink rhyolite lavas, brecciated in part. Typically very fine-grained glass or devitrified glass in which phenocrysts include feldspar, biotite and quartz. A distinct coarse-grained reddish-brown breccio-conglomerate (the Sandway Cellar Conglomerate Member) containing dispersed clasts of Lower Devonian sandstone and penecontemporaneous rhyolite occers within the rhyolite flow. | Not particularly hard, can be trimmed for use in rubble masonry. | Used locally as general building stone and rubblestone, mainly in older buildings in Kingsand and Cawsand. | Kingsand-Withnoe area, Rame Peninsula, south-east Cornwall. A continuous section is exposed in a raised beach platform from Sandway Cellar to Kingsand Beach. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood, Durrance & Bristow, 1999; Leveridge et al, 2002 | 2012-05-16 10:20:32
4127 | Sandway Cellar Conglomerate | 1 |  | Fine to coarse reddish brown conglomero-breccia with coarse- to very coarse-grained sandstone with dispersed clasts of Lower Devonian sandstone and penecontemporaneous rhyolite |  |  | Reddish brown | SANDWAY CELLAR CONGLOMERATE MEMBER | PERMIAN to PERMIAN | CONGLOMERATE | Coarse grained |  | A distinct coarse-grained reddish-brown breccio-conglomerate (the Sandway Cellar Conglomerate Member) containing dispersed clasts of Lower Devonian sandstone and penecontemporaneous rhyolite occers within the rhyolite flow |  | Used locally as general building stone and rubblestone, mainly in older buildings in Kingsand and Cawsand. | Kingsand-Withnoe area, Rame Peninsula, south-east Cornwall. A continuous section is exposed in a raised beach platform from Sandway Cellar to Kingsand Beach. | 2010-08-14 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood, Durrance & Bristow, 1999; Leveridge et al, 2002 | 2012-05-16 10:20:32
4128 | Culm Measures | 1 |  |  |  |  |  | CULM SUPERGROUP | CARBONIFEROUS to CARBONIFEROUS | SANDSTONE |  |  |  |  | ? | North and East Cornwall | 2010-05-11 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | BGS Lexicon | 2012-05-16 10:20:32
4129 | [NAME] | 4128 | Culm Measures | Formation very thick, up to 1300 m on north Cornwall coast around Bude. Marine fossils widespread, but only in infrequent units of dark grey or black, sulphurous shales ('Key Shales') with goniatite-bearing calcareous nodules, bivalve and fish remains. Trace fossils include burrows and xiphosaurid trails in thin siltstone units. | GREY | Uniform | Sandstones weather to buffish colour. | [NAME] | CARBONIFEROUS | SANDSTONE | Fine grained | Sandstones typically fine to medium grained, and usually featureless, only occasionally showing indistinct lamination or coarse bedding. Sandstone bases sharp, exhibiting broad, shallow scours, large-scale load structures and sole markings. | Grey thick-bedded, somewhat argillaceous and silty sandstones, in laterally discontinuous internally massive beds 1-5m thick and commonly amalgamated into units up to 10m thick. Very thick beds of slumped strata are also present. Grey mudstones occur as interbeds up to 1 m thick but locally packets of darker mudstone up to 20m thick with thin ironstone beds and bundles of thin sandstones are present, especially in the upper part of the formation. Distinguished from similar Crackington Formation turbidite facies by [NAME] containing units of thicker (greater than 1 m) sandstones. | Generally fairly hard, but weathered sandstones become friable. | Used as general building and walling stone where available along outcrop. | Occupies a large area extending from the north Cornwall coast around [NAME] (SS 21 06), eastwards through mid-Devon to area west of Tiverton (SS 96 13). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1972; [NAME], 1979; Edmunds et al, 1968: Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4130 | Crackington Formation | 4128 | Culm Measures | Formation very thick, up to 1000 m. Sparsely fossiliferous; on the north [NAME] (and [NAME]) coast, six named units of dark grey to black pyritic shale with goniatite- and fish-bearing calcareous nodules are present in the upper part of the formation. | GREY | Uniform | Pale grey to dark blue-grey, occasionally dark greenish | CRACKINGTON FORMATION | CARBONIFEROUS | SANDSTONE | Medium grained | The sandstones are parallel-sided '[NAME]-type' turbidites with abundant well-developed sole or flute cast structures and graded bedding. Individual beds are from a few centimetres to 0.4 m thick, rarely up to 1 m thick. Thicker sandstones are locally present, mainly in the uppermost part of the formation, but tend to be massive and lack sole structures. | Rhythmically bedded, dark blue-grey slates and mudstones, with alternating predominantly grey sandstones and siltstones. Sandstone percentage varies from 20-75%, both vertically and geographically.  Packets with abundant sandstones are commonly developed and mappable. A few thick units of slumped or destratified beds are also present in the uppermost part of the formation, as are scattered ironstone nodules. One of the most striking features of these rocks is their folding; the alternating layers of dark slates and paler sandstones making the sharp-angled chevron folds (with horizontal axial planes) standing out distinctly. | Fairly hard, resiliant. | Used as general building and walling stone where available along outcrop. | Extends from North Cornwall and coast (SX 15 97) eastwards [NAME] (SS 7010) and western Somerset (ST 06 17). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1972a; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4131 | St Mellion Formation | 4128 | Culm Measures | Formation very thick, approx 500 m. Some fossil horizons reported, mainly ammonoids in marine mudstone/shale bands. Some sandstone and siltstone beds rich in plant debris, rare rootlet beds. | DARK-GREY | Uniform | Weathers from pale to dark grey. | ST MELLION FORMATION | CARBONIFEROUS | SANDSTONE | Medium grained | Cross bedding within sandstones, and slumping structures, typical of turbiditic facies. Also interbedded shales and siltstones; some bioturbation. | Medium to very coarse grained, dark grey sandstones, locally conglomeratic or feldspathic, sometimes rich in fossil plant debris. Sandstones tend to be concentrated in medium to thickly-bedded packets Interbedded pale to dark grey mudstones, shales and siltstones. | Sandstones moderately hard, mudstones interbeds much softer. | General local building and walling stone, mainly from the sandstone facies. Sandstones quarried and used as building stones from  Dunstan and Crocadon areas. | St Mellion area (SX 39 65), between Bodmin Moor and Dartmoor, east [NAME]. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1911; Selwood, Durrance & Bristow, 1999; Leveridge et al, 2002; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4132 | [NAME] | 4131 | St Mellion Formation | Formation very thick, approx 500 m. Some fossil horizons reported, mainly ammonoids in marine mudstone/shale bands. Some sandstone and siltstone beds rich in plant debris, rare rootlet beds. | DARK-GREY | Uniform | Weathers from pale to dark grey. | ST MELLION FORMATION | CARBONIFEROUS | SANDSTONE | Medium grained | Cross bedding within sandstones, and slumping structures, typical of turbiditic facies. Also interbedded shales and siltstones; some bioturbation. | Medium to very coarse grained, dark grey sandstones, locally conglomeratic or feldspathic, sometimes rich in fossil plant debris. Sandstones tend to be concentrated in medium to thickly-bedded packets Interbedded pale to dark grey mudstones, shales and siltstones. | Sandstones moderately hard, mudstones interbeds much softer. | General local building and walling stone, mainly from the sandstone facies. Sandstones quarried and used as building stones from  Dunstan and Crocadon areas. | St Mellion area (SX 39 65), between Bodmin Moor and Dartmoor, east [NAME]. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1911; Selwood, Durrance & Bristow, 1999; Leveridge et al, 2002; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4133 | Boscastle Measures | 4128 | Boscastle Formation | Formation several hundred metres thick,  but may be more or less due to complex faulting, folding and thrusting, including tight isoclinal folding of rocks, repetitive low-angle faulting, and NW-SE strike-slip faulting, especially along coastal sections. Sparsely fossiliferous, conodonts and rare goniatites. | DARK-GREY | Uniform | Mostly dark grey to black. | BOSCASTLE FORMATION | CARBONIFEROUS | SLATE | Fine grained | Sandstones bedded on the decimetre scale, with sharp or gradational tops and bases, but no obvious internal grain-size trends. Generally structureless, but infrequent cross-laminated tops include bundling diagnostic of wave ripples.Mudstones and limestones sometimes bioturbated. | Dark grey to black pyritous slates, mudstones with thin laminated siltstones, interbedded with packets of grey, fine- to coarse-grained quartzitic sandstones. Locally, the sandstones are calcareous, shelly and occasionally accompanied by thick beds of bioclastic limestone and nodules of silicified limestone. Rare thin beds of tuffaceous mudstone, tuffs and [NAME] also occur. | Fairly hard, resiliant. | Used as general building and walling stone where available along outcrop. | Between Boscastle (SX 95 91) and [NAME] (SX 27 81), north [NAME], extending into east [NAME] (Trenault). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | McKeown et al, 1973; [NAME], 1972a; [NAME], 1972b; Selwood et al, 1985; Selwood, Durrance & Bristow, 1999; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4134 | Teign [NAME] | 4128 |  | Formation up to 100 m thick. Radiolaria are locally abundant in the cherts and siliceous mudstones, but generally indeterminate, conodonts present. | DARK-GREY | Banded | Mostly dark grey to black. | TEIGN CHERT FORMATION | CARBONIFEROUS | CHERT | Very fine grained | Well bedded, individual beds range from a few millimetres to decimetre-scale, commonly laminated. The matrix of the chert is entirely recrystallised to chalcedony (microcrystalline quartz). | Thin to medium bedded cherts, mostly dark grey to black, generally separated by subordinate black siliceous mudstone beds and partings. Also present are bluish black mudstones, and thin to medium bedded argillaceous limestones. Some areas are dominated by mudstone, others by chert or limestone; in the Boscastle area, north [NAME], the formation is dominated by mudstone. | Very hard, resiliant | Used as general building and walling stone where available along outcrop. | Occurs in klippen capping hills to the north of Launceston, extending westwards to the north Cornwall coast | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood et al, 1984: McKeown et al, 1973; Selwood, Durrance & Bristow, 1999; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4135 | [NAME] | 4134 | Teign [NAME] | Formation up to 100 m thick. Radiolaria are locally abundant in the cherts and siliceous mudstones, but generally indeterminate, conodonts present. | DARK-GREY | Banded | Mostly dark grey to black. | TEIGN CHERT FORMATION | CARBONIFEROUS | CHERT | Very fine grained | Well bedded, individual beds range from a few millimetres to decimetre-scale, commonly laminated. The matrix of the chert is entirely recrystallised to chalcedony (microcrystalline quartz). | Thin to medium bedded cherts, mostly dark grey to black, generally separated by subordinate black siliceous mudstone beds and partings. Also present are bluish black mudstones, and thin to medium bedded argillaceous limestones. Some areas are dominated by mudstone, others by chert or limestone; in the Boscastle area, north [NAME], the formation is dominated by mudstone. | Very hard, resiliant | Used as general building and walling stone where available along outcrop. | Occurs in klippen capping hills to the north of Launceston, extending westwards to the north Cornwall coast | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood et al, 1984: McKeown et al, 1973; Selwood, Durrance & Bristow, 1999; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4136 | [NAME] | 4134 | Teign [NAME] | Formation up to 100 m thick in the St Melllion area. Radiolaria are locally abundant in the cherts and siliceous mudstones, but generally indeterminate, conodonts present..   In the St Mellion area a distinctive unit of  thin bedded cherts, limestones and shales (the 'Posidonia Beds') also occurs. This contains abundant fossil pectinid bivalves and spirally striated goniatites. | GREY | Banded | Variable, from white, grey and green to bluish black; rarely jasper red. | TEIGN CHERT FORMATION | CARBONIFEROUS | CHERT | Very fine grained | Well bedded, individual beds range from a few millimetres to decimetre-scale, commonly laminated. The matrix of the chert is entirely recrystallised to chalcedony (microcrystalline quartz). | Thin to medium bedded cherts, generally separated by siliceous mudstone beds and partings. Also present are bluish black mudstone and thin to medium-bedded argillaceous limestones. Some areas are dominated by mudstone, others by chert or limestone.  In the St Mellion area, the lower part of the formation comprises siliceous mudstone with or without scattered cherts beds, and the upper part comprises cherts with thin mudstone interbeds. Various volcanic rocks, including quartz-keratophyre tuffs, basic spilitic, and felsitic [NAME], are also present. | Very hard, resiliant | Used as general building and walling stone where available along outcrop. Quarried from [NAME], [NAME], North Down Wood quarries. | Central and east [NAME], including St Mellion area, extending eastwards into Devon (Okehampton and Teign Valley). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood et al, 1984; McKeown et al, 1973: [NAME] et al, 2002; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4137 | Trambley Cove Formation | 4128 |  | Formation approx 15 m thick, poorly fossiliferous (conodonts). | GREY | Banded | Pale to dark grey, blackish. | TRAMBLEY COVE [NAME] | CARBONIFEROUS | SLATE | Very fine grained | [NAME] siltstone beds commonly cross-bedded or laminated. | Pale to dark grey or black, finely colour-banded, pyritous slates and mudstone with thin beds of siltstone. Occasional interbeds of volcanic tuff and sporadic limestone bands. The siltstone and locally the mudstone are silicified, giving the succession a cherty appearance. Greenish brown tuffaceous mudstones are locally present, especially towards the base. | Hard, resiliant | Used as general building and walling stone where available along outcrop. | From Tintagel area (SX 06 89) to the south of [NAME] (SX 32 77). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1972a; McKeown et al, 1973; Selwood et al, 1978; Selwood, Durrance & Bristow, 1999; Bristow, 2004; Leveridge & Hartley, 2006: | 2012-05-16 10:20:32
4138 | Tintagel Volcanic Formation | 4128 |  | Formation up to 90 m thick. [NAME] typically subjected to 'greenschist' metamorphism, resulting in formation of new minerals such as albite, chlorite, epidote and biotite. | DARK-GREEN | Uniform | Weather from dark green, to dark grey or blackish. | TINTAGEL VOLCANIC FORMATION | CARBONIFEROUS | LAVA | Fine grained | Pillow lavas often represented as lenses of basic lava (remnants of pillow cores) set in an intensely sheared matrix (the softer material between pilllows). | Poorly sorted, dark green to dark grey, fine-to coarse-grained basaltic calcareous tuffs with subordinate agglomerates and recrystallised carbonate-rich basaltic lavas. A few thin pink limestones occur scattered throughout the Formation. Variable proportions of basaltic tuffs and pillow lavas occur. | Fairly hard, resiliant. | Used as general building and walling stone where available along outcrop. | Best known from the [NAME] area (SX 06 89), especially [NAME], but extends around north side of Bodmin Moor via St Clether / River Inny to [NAME] area (SX 32 77). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME]; McKeown et al, 1973; Floyd, Exley & Styles, 1993; Selwood et al, 1998; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4139 | Greenstone | 1 | 'Blue elvan' | All pre variscan greenstones in Cornwall have been subject to low grade metamorphism which has resulted in the development of a mineral suite such as chlorite, prehnite, epidote and pumpellyite. Despite these changes, many greenstones do not weather rapidly, and those located around the granite intrusions are extremely durable. This contrasts with hydrothermal alteration such as carbonization, which forms soft talc minerals, and usually renders the greenstones unsuitable for exterior use. | GREEN | Uniform | Unaltered greenstones usually become a darker  colour upon weathering. | UNNAMED IGNEOUS INTRUSION, DEVONIAN TO CARBONIFEROUS | CARBONIFEROUS to CARBONIFEROUS | IGNEOUS, MEDIUM-GRAINED | Medium grained | Typically relatively structureless. | A colloquial term for a variety of basic igneous rocks (also called 'blue elvan' by quarryworkers in west Cornwall), which typically occur as narrow intrusions (dykes or sills) within the country rock. They are silica-poor in comparison to granites and acidic igneous rocks, but have higher ferromagnesian mineral content, especially amphiboles such as hornblende. This concentration of minerals often gives greenstones a dark greenish-blue, greenish grey or blackish colour. Grain size varies, but fine grained varieties make the best quality building stones. Although greenstones are a relatively minor component of the geological succession in Cornwall, individual bodies may extend for several kilometres and provide a large resource of stone. | Unaltered (eg. [NAME]) greenstones are typically very hard and durable rocks. Greenstones are commonly harder and more resistant to erosion than the surrounding country rock, and they often form prominent features such as black head near St Austell, Cataclews Point near Harlyn Bay,  and [NAME] near Menheniot. | Greenstones are extensively quarried as a source of quality strong aggregate, as for example at Greystone Quarry (near Launceston) and [NAME] ([NAME], [NAME]). However, their durable properties also make some greenstones highly suitable as building stones, and some varieties (such as Cataclews Stone) were amongst the earliest building stones to be used in Cornwall. | Quarried at several locations throughout Cornwall. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood et al, 1998; Bristow, 2001; Bristow, 2006 | 2012-05-16 10:20:32
4140 | Cataclews Stone | 4139 | Greenstone | One of the best known examples of Cornish 'greenstones' used as a building stone, worked from medieval times. Also spelt Catacleuse Stone. | DARK-GREEN | Uniform | Very dark, blackish | UNNAMED IGNEOUS INTRUSION, DEVONIAN TO CARBONIFEROUS | CARBONIFEROUS to CARBONIFEROUS | IGNEOUS, MEDIUM-GRAINED | Medium grained | Relatively massive, structureless. | A hydrous alkali dolerite intruded into upper Devonian slates. Typically crystalline, very dark green or blackish colour (due to the presence of augite). The grain size is variable, [NAME] masons seem to have favoured the finer grained variety. | Very hard weathering, resistant rock. | Quarried from Cataclews Point. Used extensively in the Padstow area, including in a number of local churches, including [NAME] and St Petroc. | Cataclews Point (SW 873 761), west side of Harlyn Bay, west of Padstow. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood et al, 1998; Bristow, 2001; Bristow, 2006 | 2012-05-16 10:20:32
4141 | Tregongeeves Stone | 4139 | Greenstone | Hornblende often occurs as bundles of sub-radiating acicular needles. In fiedl outcrop, thin veins of purplish axinite are also common. | DARK-GREEN | Uniform | Weathers darker, joint planes often lined with limonite. | UNNAMED IGNEOUS INTRUSION, DEVONIAN TO CARBONIFEROUS | CARBONIFEROUS to CARBONIFEROUS | IGNEOUS, MEDIUM-GRAINED | Medium grained | Relatively massive, structureless. Microscopically with ophitic texture. | Dark green stone, exhibiting a clear ophitic texture of short, rectangular crystals of plagioclase (oligoclase) feldspar, embedded in hornblende. The rock also contains much granular epidote and leucoxene after iron oxides. Some mica (biotite) and apatite also present. | Often heavily weathered form of greenstone, but still relatively durable. | Used as a local building stone within Pentewan area, [NAME]. | Tregongeeves, Pentewan valley, near St Austell. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Bristow, 2001; Bristow, 2004; | 2012-05-16 10:20:32
4142 | [NAME] | 4139 | Greenstone | In places extremely soft, with 'soapy' feel of talc when rubbed between fingers. Rock generally in an advanced state of decomposition. | PALE-GREEN | Spotted | Weathers pale grey to pale green. | UNNAMED IGNEOUS INTRUSION, DEVONIAN TO CARBONIFEROUS | CARBONIFEROUS to CARBONIFEROUS | IGNEOUS, COARSE-GRAINED | Coarse grained |  | A basic igneous rock, intruded as a sill into Lower Devonian Meadfoot Group slates, and then subsequently carbonatized to a mixture of talc, chlorites and various carbonates (the original olivine being replaced by talc and serpentine). Charcteristically a pale to dark greyish-green colour, often with a coarse speckled texture, sometimes blotched red. A darker coloured variant is slightly harder and contains black crystals of augite (after olivine) and feldspar laths replaced by [NAME]. The rest of the rock comprises mainly chlorite. | Relatively soft and porous, so does not weather well in exterior use. The crumbling cliffs at Duporth are due to this weak material. | Used locally, especially for interior purposes. For example, some of the pillars in Truro Cathedral, and also in [NAME], Charlestown and Holy Trinity, [NAME]. | Cliffs at Duporth Bay (SX 036 513), near St Austell. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, Barrow & MacAlister, 1909; Power & Scott, 1995; Bristow, 2001; Bristow, 2004; | 2012-05-16 10:20:32
4143 | Polyphant Stone | 4139 | Greenstone | Estimated to be approximately 32 m thick, with an exposure width of 0.5 km. Polyphant Stone is a famous, highly altered talcose rock that has been used for ornamental carvings since the 11th Century. It has been quarried since [NAME] times from old quarries  at Polyphant and adjacent hillside outcrops to the south of the River Inny. | DARK-GREEN | Uniform | Weathers (oxidises) to brownish limonite. | POLYPHANT INTRUSION | CARBONIFEROUS to CARBONIFEROUS | IGNEOUS, MEDIUM-GRAINED | Medium grained | Variably foliated. A fine banding is present  on some weathered surfaces. | A carbonatized ultrabasic intrusion. A melanocratic, very dark greenish to dark bluish metaperidotite composed of serpentinite, chlorite, talc and carbonate. Primary minerals include olivine, pyroxene, dark purplish clinopyroxene, brown amphibole, deep-red biotite, apatite and magnetite. No pale coloured minerals such as feldspar are present. The presence of water-bearing primary minerals (amphibolite and biotite) distinguishes Polyphant Stone from other peridotites within [NAME]. Associated with the Polyphant peridotite are gabbros and dolerites intruded into the host Devonian slates. | Quite a soft, porous rock which does not weather well in exterior use. Susceptible to frost action. | Used mainly for internal purposes, is a superb medium for carving and readily takes a lustrous polish. Many churches in east [NAME] have interior features made of Polyphant Stone. Occasionally employed for external use, such as [NAME]. Extensively exported out of Cornwall, particularly for use in churches (eg. Exeter and Canterbury Cathedrals). | Polyphant (SX 262 822), near Launceston. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Floyd, Exley & Styles, 1993; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4144 | [NAME] | 1 |  | Often occur in very thick successions. Fossils typically absent or very sparse, where present they are often distorted by deformation, cleavage etc. | DARK-GREY | Uniform | Often dark grey to blackish, but highly variable depending on lithologies. | PARENT DATA NOT YET ENTERED [HIERARCHY CODE] | CARBONIFEROUS to CARBONIFEROUS | SLATE | Fine grained | Varied, but cleavage often developed to a greater or lesser extent. Spotting and thin mineral veining also occurs. | [NAME] is a general term applied to rocks in Cornwall which were formerly sedimentary country rocks (of Devonian or Carboniferous age) which have been intruded by granites, or are in the vicinity of igneous intrusions, and as a result have usually become metamorphosed and/or affected by the resultant deformation. They vary considerable in colour and grain size depending on the lithologies affected, but dark, fine-grained stones are typical. They are often regarded as slates or 'metasediments'. [NAME] are frequently associated with mineralised zones around granites and other intrusions. | Often fairly hard and durable, to very hard and resiliant, particularly in the case of country rocks which occur in close proximity of granitic or doleritic intrusions and have become metamorphosed ('hornfels'). | Used throughout Cornwall wherever they occur as a general purpose building and walling stone. | Occur throughout Cornwall. Body worked depends on location of source rock. | 2010-08-13 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4145 | Saltash Formation | 4144 |  | Immensely thick formation, approximately 3900 m on north Cornwall coast. Fossiliferous, including conodonts and palynomorphs. | GREY | Uniform | [NAME]. | SALTASH FORMATION | CARBONIFEROUS to CARBONIFEROUS | SLATE | Fine grained | Occasional lamination, and local bioturbation, especially in lower parts of formation. | [NAME] and grey silty slates and mudstone with variable but very subordinate and thin beds of siltstone and sandstone. There are scattered units of thin- to thick-bedded limestone, thin- to thick-bedded sandstone (eg: Wearde Sandstone Member - see entry below), basaltic [NAME], spilites, massive and bedded hyclastites, and bedded tuffs. | Fairly hard, resiliant. | Used as roofing slate and as general building and walling stone where available along outcrop. The bridges over the Tamar at Saltash are founded on this formation, and the Saltash tunnel is driven through it. Quarried at Trehunsey Barton, [NAME], Kilquite, Bokenna Wood, [NAME], [NAME], Lantoom and Underways quarries. | From [NAME] area (SW 86 76), north [NAME] to Torquay area (SX 93 65), south [NAME]. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | House et al, 1977; Selwood et al, 1998; [NAME] et al, 2002; Bristow, 2004 | 2012-05-16 10:20:32
4146 | Wearde-Efford Greywacke | 4145 | Wearde-Efford Grit | Formation approximately 25 m thick. Upper and lower boundaries confromable and transitional into slate-dominated facies of parent [NAME]. | GREY | Uniform | [NAME]. | WEARDE SANDSTONE MEMBER | CARBONIFEROUS to CARBONIFEROUS | SANDSTONE | Medium grained | Cross-bedding features occur in the thickly bedded channel sandstones. Mudstones with sandy laminae and lenses. | A distinctive member comprising thickly bedded massive (channel) sandstones with rare interbeds of mudstone and siltstone, and non-channel sandstones: Fine- to coarse-grained sandstone in parallel beds up to 1m thick with interbeds of interlaminated siltstone and mudstone. Interbedded mudstones contain sandstone streaks, lenses, thin to thick laminae and thin beds. Associated basaltic lava and hyaloclastite form an important but subordinate facies. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. Quarried at Tor Lane. | South east Cornwall, and Plymouth area. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, 1907; [NAME] et al, 2002 | 2012-05-16 10:20:32
4147 | [NAME] | 1 |  | Thick formation, up to 1500 m. | GREY | Banded | Often dark grey, but highly variable depending on constituent lithologies. | [NAME] | DEVONIAN | BRECCIA | Pebble grade | Characteristically a chaotic jumble of mixed rock types and large scale slump, slide and gravity flow structures. Some individual beds and lithologies such as sandstones and quartzites exhibit lamination and folds respectively. | An olistostrome deposit, comprising grey slaty mudstone with framework and matrix of breccias and conglomerates, interbedded sandstone, felsic and mafic tuffs/[NAME] and metamorphic rock breccias. Olistoliths include Ordovician quartzite, Silurian and early to mid Devonian limestone, sandstone, breccia, metamorphic and mafic/ultramafic igneous rocks. Contemporaneous basic and [NAME], volcanic breccias and minor intrusions. | Variable, depending on constituent clasts. Large (Ordovician) quartzite boulders very resistant, conglomerates with sedimentary clasts softer. | Used locally as a general purpose walling and building stone; for example at Gorran Haven and Veryan. | Roseland Peninsula and Meneage, south [NAME]. Including along much of coast between Pendower Beach and Mevagissey, also [NAME], [NAME], and further east in cliffs near Gorran Haven. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Holder & Leveridge, 1986; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4148 | [NAME] | 1 |  | Immensely thick formation, approximately 5400 m believed present. Sparsely fossiliferous, plant remains occur in thin, [NAME] seams near Pendower Beach and [NAME]. | GREY | Uniform | [NAME], dark greenish grey. | PORTSCATHO FORMATION | DEVONIAN | SANDSTONE | Fine grained | Turbidite units exhibit graded bedding and flute casts, especially on the bases of beds. | Alternating grey or greenish grey, normally graded sandstone beds (up to 2m thick) with interbedded grey slates and slaty mudstones. Sporadic beds of siltstone also occur. | Very durable, resiliant. | Used locally as general purpose building and walling stone where available along outcrop. Sandstones from this formation were used to construct the 16th Century castle at St Mawes. | South Cornwall, especially in the Falmouth area and inland to east of Truro. Also well exposed at Gerrans Bay, and around St Mawes, and extending to the western side of the Lizard Peninsula (from Looe Pool to Jangye-ryn). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge, Holder & Goode, 1990; Bristow, 2004; Leveridge & Hartley, 2006; Hollick, Shail & Leveridge, 2006 | 2012-05-16 10:20:32
4149 | Jacket's Point Formation | 1 |  | Formation approximately 100 m thick. | GREY | Uniform | Pale grey to dark grey. | JACKET'S POINT [NAME] | DEVONIAN | SLATE | Fine grained | Slates with well developed cleavage. | Grey slates and mudstone with subordinate fine- to medium-grained sandstones, conglomerate and associated volcanic rocks. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. | [NAME] to [NAME], north Cornwall. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Selwood & Thomas, 1986; Selwood et al, 1998 | 2012-05-16 10:20:32
4150 | Trevose Slate | 1 |  | Formation immensely thick, 3900 m. Fossils found within the slates include the ubiquitous crinoid ossicles, goniatites (sometimes pyritised), trilobites, fish, brachiopods and corals. | GREY | Uniform | Pale grey to dark grey. | TREVOSE SLATE FORMATION | DEVONIAN | SLATE | Very fine grained | Slates with well developed cleavage, some pale grey siltstones exhibit lamination, others (typically dark grey) are structureless. | Pale to dark grey slates with regular interbeds of siltstone, from 0.03-0.10m thick. Sporadic thin beds of sandstone and limestone also occur, the latter occuring particularly in the upper part of the formation. Also contains some basic igneous volcanic ash horizons and dolerite intrusions. | Fairly hard, resiliant. | Used as roofing slate ([NAME]) and as general building and walling stone where available along outcrop. | West of Bodmin Moor, to Pentire Point, [NAME] and [NAME]. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | House, 1961; Selwood et al, 1998; Bristow, 2004 | 2012-05-16 10:20:32
4151 | St Issey Stone | 4150 | Trevose Slate | Thickness of unit not known. | PALE-GREY | Uniform | Pale cream, or rusty brown. | TREVOSE SLATE FORMATION | DEVONIAN | SANDSTONE | Fine grained | Cleavage / lamination fairly well developed. | Characteristic pale grey or pale greyish-green slate merging into fine siltstone, with fairly well developed cleavage or lamination permitting easy splitting into tabular slabs. Particularly well suited for walling purposes. Its pale colour is a useful distinguishing feature. | Fairly hard, resiliant. | Quarried in the Wadebridge area and used as a general slate for a variety of purposes where a natural stone finish is required, especially walling. Also used in the construction of 'Cornish hedges' alongside new road schemes. | Wadebridge area, near Padstow. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4152 | [NAME] | 1 |  | Thickness of formation not known. Passes upwards into [NAME]. | GREY | Uniform | [NAME]. | BEDRUTHAN FORMATION | DEVONIAN | SLATE | Fine grained | Many of the siltstones exhibit planar, occasionally cross-lamination. | Varied lithologies, but mainly siltstones and sandy siltstones, with subordinate slates. The relative lack of slates and preponderance of siltstones distinguishes these beds from the overlying Trevose Slates Formation. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. Quarried at Tredinnick, [NAME], Camel and [NAME] quarries. | West Cornwall coast, from Carnewas to northern end of Bedruthan Steps. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002; Bristow, 2004 | 2012-05-16 10:20:32
4153 | [NAME] | 1 | [NAME] | Formation approximately 100 m thick. Base transitional with [NAME]. | DARK-GREY | Uniform | Weather blackish. | [NAME] | CARBONIFEROUS to CARBONIFEROUS | SLATE | Fine grained | Sparse. Some lamination occurs within the siltstone beds. | Dark grey to black lustrous slates and slaty mudstone with grey siltstone laminae, and subordinate thin to thick medium- to coarse-grained grey-green sandstone beds. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. Quarried at Burraton. | South east Cornwall, and Plymouth area. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002 | 2012-05-16 10:20:32
4154 | [NAME] | 1 |  | Thickness of Formation unknown. | PALE-GREEN | Uniform | Weathers to darker grey. | TAVY FORMATION | DEVONIAN | SLATE | Fine grained | Sparse. Some lamination occurs within the siltstone beds. | Pale green and grey-green slates and silty mudstones, with some thin fine-to medium-grained sandstone beds and lenses, occasional siltstones. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. Quarried at Pentille quarry. | South east Cornwall, and Plymouth area. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4155 | [NAME] | 1 | Trevillet Slate | Formation estimated 500-800 m thick. Restricted fossil fauna, including rhynchonellids and spiriferids in siltstones, along with crinoid debris and bryozoans. Occasional burrow fills. | PALE-GREEN | Spotted | Tends to weather darker. Frequently becomes iron stained along joint surfaces, small brownish spots of weathered pyrite may also appear. | TREDORN SLATE FORMATION | DEVONIAN | SLATE | Very fine grained | Well developed cleavage. Metamorphism to 'greenschist' facies has caused development of chlorite and mica. Cubic crystals of pyrite are ubiquitous, sometimes large, up to 50 mm. | Pale green to grey-green or blackish chloritic slate and silty mudstones, faintly banded in parts. Locally interbedded with thinly bedded, commonly lenticular bioclastic limestone and dolomite beds, up to 0.15m thick. Siltstones and fine-grained sandstones, with rare tuff beds, also occur. | Fairly hard, but pyrite susceptible to weathering. | Used as roofing slate and as general building and walling stone where available along outcrop. Quarried at Trebarwith, Trecarne and Trevillet from 19th Century, and  also to west of Boscastle (California, Welltown, Grower and Boscastle Cliff quarries) often from base of sea cliffs, and hauled by cable to cliff tops. | North Cornwall, from Tregardock to south of South Petherwin. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME]; McKeown et al, 1973; Selwood et al, 1998; [NAME] et al , 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4156 | Trevillet Slate | 4155 | [NAME] | Formation estimated 500-800 m thick. Restricted fossil fauna, including rhynchonellids and spiriferids in siltstones, along with crinoid debris and bryozoans. Occasional burrow fills. | PALE-GREEN | Spotted | Tends to weather darker. Frequently becomes iron stained along joint surfaces, small brownish spots of weathered pyrite may also appear. | TREDORN SLATE FORMATION | DEVONIAN | SLATE | Very fine grained | Well developed cleavage. Metamorphism to 'greenschist' facies has caused development of chlorite and mica. Cubic crystals of pyrite are ubiquitous, sometimes large, up to 50 mm. | Pale green to grey-green or blackish chloritic slate and silty mudstones, faintly banded in parts. Locally interbedded with thinly bedded, commonly lenticular bioclastic limestone and dolomite beds, up to 0.15m thick. Siltstones and fine-grained sandstones, with rare tuff beds, also occur. | Fairly hard, but pyrite susceptible to weathering. | Used as roofing slate and as general building and walling stone where available along outcrop. Quarried at Trebarwith, Trecarne and Trevillet from 19th Century, and  also to west of Boscastle (California, Welltown, Grower and Boscastle Cliff quarries) often from base of sea cliffs, and hauled by cable to cliff tops. | North Cornwall, from Tregardock to south of South Petherwin. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME]; McKeown et al, 1973; Selwood et al, 1998; [NAME] et al , 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4157 | Tintagel Slate | 4155 | [NAME] | Formation estimated 500-800 m thick. Restricted fossil fauna, including rhynchonellids and spiriferids in siltstones, along with crinoid debris and bryozoans. Occasional burrow fills. | DARK-GREEN | Uniform | Tends to weather darker. Frequently becomes iron stained along joint surfaces, small brownish spots of weathered pyrite may also appear. | TREDORN SLATE FORMATION | DEVONIAN | SLATE | Very fine grained | Well developed cleavage. Metamorphism to 'greenschist' facies has caused development of chlorite and mica. Cubic crystals of pyrite are ubiquitous, sometimes large, up to 50 mm. | Dark green to blackish chloritic slate and silty mudstones, faintly banded in parts. Locally interbedded with thinly bedded, commonly lenticular bioclastic limestone and dolomite beds, up to 0.15m thick. Siltstones and fine-grained sandstones, with rare tuff beds, also occur. | Fairly hard, but pyrite susceptible to weathering. | Used as roofing slate and as general building and walling stone where available along outcrop. Quarried at Tintagel cliffs since 17th Century. | North Cornwall, from Tregardock to south of South Petherwin. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME]; McKeown et al, 1973; Selwood et al, 1998; [NAME] et al , 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4158 | [NAME] | 4155 | Lower Delabole Slate | Formation 30-50 m thick. Sparsely fossiliferous, but famed for 'Delabole butterfly', a fossil spiriferid [NAME], often found distorted by deformation which affected the slates. | GREY | Uniform | Tends to dullen and become paler, sheen fades on weathering, Frequently becomes iron stained along joint surfaces. | DELABOLE MEMBER | DEVONIAN | SLATE | Very fine grained | Well developed cleavage. Metamorphism to 'greenschist' facies has caused development of chlorite. | Distinctive greenish-grey to silvery-grey slates, with almost silky lustre. Occasional bands of thin siltstone also occur. | Hard, very resistant to weathering. | One of the best known and highest quality roofing slates in Cornwall, continuously worked since Tudor times. Widely used in Cornwall and beyond, nationally and internationally, exported out of Port Issac. | Isolated exposures in the vicinity of Delabole village and [NAME], north Cornwall. Formerly worked in quarries south of Tintagel Island. Widely used in Cornwall and beyond. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1972a; Selwood et al, 1998; Selwood, Durrance & Bristow, 1999; Bristow, 2001; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4159 | Upper Delabole Slates | 1 |  |  |  |  |  | UPPER DELABOLE SLATES | DEVONIAN | SLATE |  |  |  |  | ? | ? | 2010-05-11 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | BGS LExicon | 2012-05-16 10:20:32
4160 | Plympton Slates | 1 | Purple and Green Slates | Thickness of formation not known. | PURPLE | Uniform | Colour mottling and transposition of colour by fluids may occur near faults. Green reduction spots are sporadically formed. | [NAME] | DEVONIAN | SLATE | Fine grained | Cleavage well developed. Some lamination in siltstone horizons. | Brownish purple to purplish red cleaved slates and mudstone with fine- to coarse-grained siltstone and fine-grained sandstones. Colour of siltstones and siltstones variable, includes yellowish to blue-green. Interdigitates in the Tavy Basin with [NAME], but purplish-red colour of slates and mudstones distinguishes these from similar beds in Tavy Formation (greenish grey slates and mudstones). | Fairly hard, resiliant. | Used as roofing slate and as general building and walling stone where available along outcrop. Quarried at Wiveliscombe quarry. | South east [NAME] (Liskeard area), and extends eastwards beyond Plymouth towards [NAME], [NAME]. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, 1907; Burton & Tanner, 1986;  [NAME] et al, 2002 | 2012-05-16 10:20:32
4161 | Grampound Grit | 1 |  | Thickness unknown. Virtually unfossiliferous. | GREY | Uniform | Sandstones often grey-blue when freshly exposed, weathering to a rusty brown. Siltstones weather yellowish-green. | GRAMPOUND FORMATION | DEVONIAN | SANDSTONE | Fine grained | Some sandstones exhibit normal grading and cross-lamination. | Thinly interlaminated grey to dark grey slaty mudstones and siltstones, with sporadic but regularly bedded, thin sandstones and sparse lenticular limestones. Sandstone units fine-grained, and grey-brown to blue-grey in colour. Siltstones typically quartzo-feldspathic, laminated  grey-brown to olive grey. | Fairly hard, resiliant. | Used locally as general purpose building and walling stone where available along outcrop. Quarried at Tredinnick, near Grampound and several other localities. Widely used in older buildings in Grampound and adjoining areas. | Exposed along the Cornish coast between Perranporth (SW 755 545) to north of [NAME] (SW 725 522). Inland it extends across the district to the area between Pentewan and Grampound. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge, 2006; Leveridge & Hartley, 2006; Hollick, Shail & Leveridge, 2006 | 2012-05-16 10:20:32
4162 | Treworgans Sandstone | 4161 | Grampound Grit | Member up to 40 m thick. Unfossiliferous. | GREY | Uniform | Yellow weathering. | TREWORGANS SANDSTONE MEMBER | DEVONIAN | SANDSTONE | Medium grained | Relatively structureless, immature sandstones. | Thick to very thick-bedded (up to 6 m), medium- to coarse-grained sandstones (locally pebbly), with subordinate dark grey interbeds of grey   slaty mudstone and yellow-green laminated siltstone. Characteristically these sandstones comprise approximately equal proportions of subangular quartz, feldspar and lithic grains, and contrast with other sandstones in the Gramscatho Group which are fine-grained, quartzo-feldspathic sandstones. | Fairly hard, resiliant. | Used locally as general purpose building and walling stone where available along outcrop. | Present at least along the northern margin of the [NAME] district, and northeast corner of the Falmouth district. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge, 1987; Leveridge, Holder & Goode, 1990; Hollick, Shail & Leveridge, 2006 | 2012-05-16 10:20:32
4163 | Staddon Grits | 1 |  | Approximately 500 m thick. | PURPLE | Uniform | [NAME], purplish grey. | STADDON FORMATION | DEVONIAN | SANDSTONE | Fine grained | Numerous structures in sandstones, including ripple lamination, cross-bedding and infilled channels. | Medium to thick beds (1-4 m [NAME]), often massive purplish grey, fine- to medium-grained sandstone, thickening and coarsening upwards with thin interbedded grey slates, mudstones and siltstones. Occasional conglomerates. | Hard, resiliant, forming some of the highest non-granite land in Cornwall. | Used locally as general building and walling stone where available along outcrop. Quarried at Lower Clicker, [NAME], and used in the Kingsand area, south of [NAME] and near Maker. | Known to occur as an extended band across Cornwall from north Cornish coast (Trenance Point) to south [NAME] coast (south of [NAME]) via the high ground of St Breock Downs and Bodmin. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4164 | Meadfoot Slate | 1 | [NAME] | At least 1300 m thick. | GREY | Uniform | Pale grey to dark grey. Sandstones become brownish. | BOVISAND FORMATION | DEVONIAN | SLATE | Fine grained | Most of the slaty rocks have developed a strong cleavage. | Slates and slaty mudstone, medium to dark grey, with thin sandstone beds (medium-grained greywackes, and local quartz arenites), and sporadic thin limestone beds. Packets of thick quartzitic sandstone beds are present in the form of the Upper and Lower Longsands Sandstone members (see below). Some slates exhibit red colouration due to iron oxides. | Fairly hard, resiliant. Typically not  high quality due to pyrite content. | Used locally as general building and walling stone where available along outcrop. Quarried at Bake Wood, St Nonna's Wood, Hobbs Park Farm, Holmbush near St Blazey. | South east Cornwall ([NAME]), and Plymouth area. Also Cornish coast around Newquay. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Ussher, 1907; [NAME] et al, 2002; Hollick, Shail & Leveridge, 2006 | 2012-05-16 10:20:32
4165 | [NAME] | 1 | [NAME] | Combined thickness of 420 m.  Sparsely fossiliferous. | GREY | Uniform | Pale grey to dark grey. | BOVISAND FORMATION | DEVONIAN | SANDSTONE | Medium grained | Sandstones exhibit fining-up sequences. Normally graded bedding, cross and parallel lamination, and load structures are also displayed. | Dominantly sandstone in sedimentary cycle, with occasional mudstone, siltstone and subordinate limestone beds up to 0.5 m thick. Sandstone of variable type, thin to thick beds, fine- to coarse-grained; sporadic packets of quartzitic sandstone also present. Passes conformably up into slaty mudstone of the undivided Bovisand Formation where sandstone cycles die out. | Fairly hard, resiliant. Sandstones show a brownish honeycomb weathering. | Used locally as general building and walling stone where available along outcrop. Quarried at Hendergulling. | South east Cornwall, and Plymouth area. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002 | 2012-05-16 10:20:32
4166 | Dartmouth Slates | 1 |  |  | GREY | Uniform |  | DARTMOUTH GROUP | DEVONIAN | SLATE |  |  |  |  | ? | South east Cornwall, and Plymouth area. | 2010-05-11 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | BGS Lexicon | 2012-05-16 10:20:32
4167 | Dartmouth Slates | 4166 |  | Formation approximately 300 m thick. | GREY | Uniform | Pale grey to dark grey. | BIN DOWN FORMATION | DEVONIAN | SLATE | Fine grained | Sandstones and siltstones sometimes exhibit slump structures. | Grey slaty mudstones and pale grey medium-grained quartzitic sandstone with interbedded, apparently extensively silicified basic lava and volcaniclastic rocks (pyroclastites and hyaloclastites). [NAME] contrasts with the underlying Whitsand bay Formation (purple and green). | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. | South east Cornwall, and Plymouth area. | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002; Bristow, 2004; Leveridge & Hartley, 2006 | 2012-05-16 10:20:32
4168 | Dartmouth Slates | 4166 |  | Formation immensely thick, 3300 m. Fossils occasional, non marine, notably  freshwater fish, pteraspids and acanthodians | PURPLE | Uniform | Dark purple, dark grey. | [NAME] | DEVONIAN | SLATE | Very fine grained | Most of the slaty rocks have developed a strong cleavage. Sandstones sporadically exhibit planar laminations and ripples. | Mainly purple, purple red and pale grey-green slates and siltstones. Occasional sandstones occur, thin to medium beds of grey-green sandstones and sporadic packets of pale grey quartzite sandstone beds. Local mottling and blebbing due to bioturbation, dispersed sedimentary clasts and volcanic detritus present. Towards the top of the formation, thin bands of sandstone become more common, and phosphatic concretions occur in the mudstones. | Fairly hard, resiliant. | Used locally as general building and walling stone where available along outcrop. | South east Cornwall ([NAME]), and Plymouth area (Whitsand Bay and Rame Head). Also Cornish coast around Newquay (from Watergate Bay). | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Leveridge et al, 2002; Bristow, 2004; Leveridge & Hartley, 2006; Hollick, Shail & Leveridge, 2006 | 2012-05-16 10:20:32
4169 | [NAME] | 1 |  | Total thickness not known. |  | Mottled | Highly variable, depending on rock type. | LIZARD COMPLEX | DEVONIAN | METAMORPHIC ROCK, MIGMATITIC |  | Relict flow banding and ptygmatic folds in magmatic rocks; varieties of serpentinite and gabbro often banded, spotted or mottled | Ophiolite complex comprising metamorphic rocks of extremely varied composition, chemistry and grain size, including ultramafic peridotites and serpentinites, layered and massive basic gabbros, basaltic dyles (epidiorites), magmatic schists and granitic gneisses, pillow lavas (Mullion Island) and associated cherts. Colours extremely variable, from blackish epidiorites, to green or reddish serpentinites, varieties of serpentinite and gabbro often banded, spotted or mottled. | Variable depending on rock types, from highly resistant gabbros and gneisses to softer serpentinites and schists. | Used locally as a general purpose building and walling stone. | Lizard Peninsula, south Cornwall. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Flett & Hill, 1946; Floyd, Exley & Styles, 1993; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4170 | Hornblende schist | 4169 |  | Other schists occur and grade into the typical; hornblende schist type. These include mica schists and a grey, coarser-grained feldspathic variety (which lacks epidote) and has a rough, irregular foliation. This form occurs around Traboe and Polkerth. | DARK-GREEN | Banded | Variable, but often dark greyish or blackish. | LIZARD HORNBLENDE SCHISTS | DEVONIAN | METAMORPHIC ROCK, SCHISTOSE | Medium grained | Perfect foliation, split surfaces often appearing  flat and parallel, so they readily split into thin slabs. | Typically dark green to blackish rocks, seldom coarse-grained, sometimes fine-grained and silky. Rich in hornblende, with thin feldspar folia. Characteristic is the abundance of lenticles and bands of yellow epidote which may vary in thickness from 0.1mm to 30 cm. Small pale green grossularite garnets are also present. | Relatively soft, readily splits along foliation surfaces. | Rarely furnished stone of sufficient quality for building houses, but foliated, slabby nature was suitable for local walling purposes. | Lizard Peninsula, south [NAME]. These rocks cover a considerable area of the peninsula, and are well exposed in coast section south of [NAME], also around Landewednack and Traboe. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Flett & Hill, 1946; Floyd, Exley & Styles, 1993; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4171 | Serpentine | 4169 |  | Main minerals include olivine and enstatite; feldspar is very scarce. Iron ores, chromite and tremolite are also present. | GREEN | Spotted | Dark green or dark red-brown. [NAME] colouring due to decomposition to iron oxides. | SERPENTINE (LIZARD COMPLEX) |  | SERPENTINITE | Coarse grained |  |  |  | Walling, decorative | Manchester usage | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | GM Buildings Spreadsheet | 2012-05-16 10:20:32
4172 | Kennack Gneiss | 4169 |  | Grain size is variable (especially within the acid component), and is sometimes very coarse, approaching a fine pegmatite, although felsitic varieties also occur. It is never porphyritc. An intensely red coloured variety, very rich in feldspar, with quartz and muscovite > biotite, occurs at [NAME]. | GREY | Banded | Pale to dark grey. | KENNACK GRANITE AND GNEISS | DEVONIAN | METAMORPHIC ROCK, MIGMATITIC | Medium grained | Banding, fluxion banding, foliation and veinlets are all characteristic structures of thisgranite-gneiss. Close spaced joints are also typical. | Mesocratic granite-gneiss generally of pale greyish colour, consisting of mixed basic (blackish or dark green coloured with hornblende, biotite) and acidic (white, pale pinkish or pale yellowish colour with quartz and feldspar) mineral components. The quartz and feldspar components seldom carry muscovite or biotite (contrasting with typical Cornish granites), and occasionally grade into quartz veins. | Readily weathers, there are no granite tors or crags. | Being closely jointed, this rock does not provide large blocks suitable for building  purposes. However, it has minor local use as a general purpose walling stone at Erisey, Gwendreath and Clahar and has been dug from pits in these areas. | Lizard Peninsula, south [NAME]. Well exposed on the coast from Kennack Sands south via Cadgwith to Pen Voose. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Flett & Hill, 1946; Floyd, Exley & Styles, 1993; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4173 | [NAME] | 1 | [NAME] | Fine-grained and very coarse-grained varieties of the gabbro occur, but usually only in veins or segregation patches. | GREY | Spotted | Pyroxene typically weathers brownish; deep prolonged weathering eventually produces a yellowish clay with small fragments of the primary minerals. | UNNAMED IGNEOUS INTRUSION, DEVONIAN | DEVONIAN | IGNEOUS, COARSE-GRAINED | Coarse grained | The main gabbro intrusion rarely shows any gneissose, schistose or 'augen' structures, or any foliation, although all these structures may be present in the smaller gabbro dykes. | Coarsely crystalline mesocratic igneous rock, often with an overall grey green colour. Its crystals vary from 7 to 15 mm in length, and comprise dark brown  or bronzy pyroxene, [NAME] greenish actinolite. A characteristic variety at Coverack (called troctolite) is composed of dark red serpentine (weathered olivine) with white spots of feldspar; although south of Coverack, at Perpean Cove, the troctolite is usually a dark green colour and more reminiscent of the typical gabbro. | Hard, durable, resistant rock. | Used locally as a general purpose building and walling stone. Quarried at St Keverne. | Lizard Peninsula, south [NAME]. Well exposed on the coast from Coverack to Porthoustock Point. | 2010-08-12 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Flett & Hill, 1946; Floyd, Exley & Styles, 1993; Selwood, Durrance & Bristow, 1999; Bristow, 2004 | 2012-05-16 10:20:32
4174 | Veinstone | 1 | Minestone |  |  |  | Usually dark coloured, characteristic staining may relate to metals present, eg. green stain for copper mineralisation. | PARENT DATA NOT YET ENTERED [HIERARCHY CODE] | PERMIAN to PERMIAN | NOT ENTERED | Very fine grained | Structure of veinstone / minestone may exhibit small veins of mineralised quartz, or crystal vugs etc. | Extremely variable depending on the geology of the mineralised areascircumstances. Examples: Wall made from angular blocks of veinstone and tourmalinised country rock ('[NAME]'), [NAME], near St Austell. [NAME] likely to have originated from nearby Charlestown United Mine. White quartz stone used in buildings north of the Camel Estuary and southwest of Truro in the Kea area. Engine houses at Wheal Kitty, St Agnes. | Often very durable, hard and  resistant. rocks due to metamorphic and mineralisation processes. | Used locally as general purpose walling and building stone, especially in older buildings in mineralised areas. For example, early medieval buildings often use stones that may have originated from tin streaming, and 18th and 19th century buildings often use stone which came from underground mining. | Throughout Cornwall, wherever mine workings and metalliferous areas occur. Type depends on location of source rock in mine or metalliferous area | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Bristow, 2001 | 2012-05-16 10:20:32
4175 | Sandstone | 1 |  |  |  |  |  | PARENT DATA NOT YET ENTERED [HIERARCHY CODE] |  | SANDSTONE |  |  |  |  | ? | ? | 2010-08-11 00:00:00 | [NAME] | Cornwall Council | Cornwall English Heritage Atlas Area | Cornwall Buildings Sheet | 2012-05-16 10:20:32
4176 | [NAME] | 4108 | [NAME] | The largest block of granite ever extracted in SW England came from [NAME], weighing in at a claimed 2738 tonnes. | PALE-GREY | Uniform | Variable, but often darker. | CARN BREA INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | The Carnmenellis granite sometimes shows a preferred orientation of the constituent minerals (foliation) giving it a gneiss-like appearance. The most intense zone of tin and copper mineralisation in the whole of the Cornubian orefield lies on the northern flanks of the Carnmenellis granite. | A leucocratic to mesocratic, biotite mica granite, often rich in feldspar megacrysts, averaging approximately 20mm in length. Biotite mainly occurs as aggregated 'clumps'. A medium granite variant of the Carnmenellis granite occurs within the central of the pluton, and may represent a separate later intrusive phase. This variant is typically is megacryst poor, and biotite tends to occur as isolated grains. | Very hard, resistant, durable. | Granite has been extensively quarried in the south eastern part of the Carnmenellis granite, notably in the parish of [NAME], and formerly used as building stone. [NAME] provided the stone for the exterior of Truro Cathedral, and [NAME] was used to construct [NAME], Falmouth and St Mawes Castle. | A circular granite outcrop, approximately 12 km wide, centered on Carnmenellis, encompassing the area between Praze and Brill. Two smaller granite areas adjoin the main outcrop: [NAME] (south of [NAME]) and Carn Marth (north of the main [NAME] intrusion). | 2010-05-17 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1934; Al-Turki & Stone, 1978; Dangerfield & Hawkes, 1981; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32
4177 | Carn Marth Granite | 4108 | [NAME] | The largest block of granite ever extracted in SW England came from [NAME], weighing in at a claimed 2738 tonnes. | PALE-GREY | Uniform | Variable, but often darker. | CARN MARTH INTRUSION | PERMIAN to PERMIAN | GRANITE, COARSE-GRAINED | Coarse grained | The Carnmenellis granite sometimes shows a preferred orientation of the constituent minerals (foliation) giving it a gneiss-like appearance. The most intense zone of tin and copper mineralisation in the whole of the Cornubian orefield lies on the northern flanks of the Carnmenellis granite. | A leucocratic to mesocratic, biotite mica granite, often rich in feldspar megacrysts, averaging approximately 20mm in length. Biotite mainly occurs as aggregated 'clumps'. A medium granite variant of the Carnmenellis granite occurs within the central of the pluton, and may represent a separate later intrusive phase. This variant is typically is megacryst poor, and biotite tends to occur as isolated grains. | Very hard, resistant, durable. | Granite has been extensively quarried in the south eastern part of the Carnmenellis granite, notably in the parish of [NAME], and formerly used as building stone. [NAME] provided the stone for the exterior of Truro Cathedral, and [NAME] was used to construct [NAME], Falmouth and St Mawes Castle. | A circular granite outcrop, approximately 12 km wide, centered on Carnmenellis, encompassing the area between Praze and Brill. Two smaller granite areas adjoin the main outcrop: [NAME] (south of [NAME]) and Carn Marth (north of the main [NAME] intrusion). | 2010-05-17 00:00:00 | D Cameron | Cornwall Council | Cornwall English Heritage Atlas Area | [NAME], 1934; Al-Turki & Stone, 1978; Dangerfield & Hawkes, 1981; Bristow, 2001; Bristow, 2004 | 2012-05-16 10:20:32