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The majority of the Triassic Sandstones found in Worcestershire are from the fluvially deposited Sherwood Sandstone Group (named after its type outcrop in Nottinghamshire) which outcrops across the centre and north of the county. The group consists of red, brown and grey sandstones, commonly pebbly or conglomeratic at the bases of beds, interbedded with red and brown siltstones and mudstones.
From oldest to youngest; the Sherwood Sandstone is made up of the Kidderminster Formation (previously known as the Bunter Pebble Beds), Wildmoor Sandstone Formation (Upper Mottled Sandstone) and the Bromsgrove Sandstone Formation (Lower Keuper Sandstone). Of these the Bromsgrove Sandstone Formation is the most widely used for building stone while the Kidderminster Formation has mainly been exploited for sand and gravel and the Wildmoor Sandstone’s softness makes it as suitable for cave digging as it isn’t for building.
Overlying the group is the Mercia Mudstone Group which has generally been used only for clay with the exception of the Arden Sandstone Formation which is an important stone in some areas.
A grey variety of Bromsgrove Sandstone quarried at Hadley, near Ombersley, since before 1800. There is also a smaller amount of red sandstone in the quarry, mottled with the grey.
The stone has small patches of harder cement which appear as slightly protruding paler patches about 0.5cm across. Also occasionally present are fragments of carbonised plant remains often ringed by a halo of iron or even copper mineralisation.
The stone has been used for a number of construction and restoration projects in the mid-19th Century, including Worcester City Walls, Worcester Cathedral, St Stephen’s Church in Barbourne and St Nicholas’ Church, Droitwich.
Quarried from the river cliff at Ross-on-Wye, ‘Ross Stone’ is a soft, deep chocolate brown-coloured, medium-grained sandstone from the Brownstones Formation. Green-grey reduction spots and stripes in the rock are very common and pebbles of quartz or mud intraclasts are often present. The sandstone is used extensively in the older buildings of Ross-on-Wye, as well as for boundary walls to Victorian brick-built villas.
Not a true metamorphic marble but a polishable micritic limestone packed with abundant gastropod fossils – the freshwater snail Viviparus – from the Peveril Point Member of the Lower Cretaceous age Durlston Formation. It was quarried and mined on the Isle of Purbeck, Dorset (the peninsula south of Corfe Castle), where several beds up to a metre thick occur between layers of soft marine clays and mudstones. The main outcrop runs due west from Peveril Point in Swanage and was quarried as far inland as Downshay Farm. In colour it can vary from green to red or brown depending on whether glauconite or the iron minerals haematite or limonite, respectively, are present.
Ubiquitous as a decorative stone – often for columns – in high status buildings across the country, a notable local example of its use is in the columns and the stone tombs of Prince Arthur and King John in Worcester Cathedral. It is used in some capacity in almost all the Cathedrals of southern England and Wales including Exeter, Ely, Norwich, Chichester, Salisbury, Lincoln, Llandaff, Southwark, Canterbury and Westminster Abbey.
Medium to coarse sandstones occasionally with layers of quartz pebbles which outcrops most of the South-east corner of Herefordshire. Compared to the underlying Raglan Mudstone and St Maughans Formations the Brownstones are both more dominated by sandstones and more uniform in appearance. Deep brown or even purple coloured, the occurrence of bands and spots of pale green are characteristic, particularly in Ross-on-Wye. Further north the boundary between them and the underlying St Maughans Formation is gradational and so distinguishing the two can be problematic. Quartz pebbles, occasionally present in the upper parts of the formation around Ross, are lacking in the St Maughans and so serve to differentiate the Brownstones is present.
Igneous rubble stone used in Malvern and around the Malvern Hills. A variety of lithologies make up the Malvern Hills of which diorite and tonalite (intermediate between granite and basalts) are the most common. Granites, pegmatites, dolerites, basalts and ultramfic lithologies also occur. Many of the rocks have been sheared and altered by fault movement, particularly south of the Wyche, giving them the appearence of high-grade metamorphic rocks. These are less used for building however as they tend to be more fissile. Owing to the highly fractured nature of the rock, it is almost impossible to produce dimension stone leading to the distinctive random rubble style of construction of Malvern buildings.
A great number of quarry operated in the hills, mostly extracting rock for aggregate but also for building. The last of these, Tank Quarry on North Hills, ceased to operate in the 1970s.
A green-grey variety of St Maughans Sandstone quarried in the Ridgeway Cross area and used extensively in Malvern. It can be difficult to distinguish from the Halesowen Formation which is also occasionally used in the area. Cradley Stone lacks the iron nodules sometimes seen in Carboniferous Sandstones.
Bishop’s Frome Limestone
A calcrete, formed within the soil horizon during the Devonian, this rubbly limestone occurs at the boundary between the Raglan Mudstone and St Maughans Sandstone and is not widely used for building. Some use is made in Bishop’s Frome but generally it has been exploited for lime-burning. It also forms an important source for tufa due the impermeable mudstones beneath generating lines of spring rich in dissolved calcium carbonate which precipitate limestones over mossy falls.
A blueish-grey lime mudstone used quite widely in South Worcestershire. Few if any traces remain of the quarries which were presumably backfilled and now lie under agricultural land. Originally most building may have been rendered as The Lias generally weathers quite poorly when exposed. It is easily recognised by its pale blueish colour, thin tabular blocks and characteristic thin laminae of coarse and fine material. Fossils, mainly bivalves, are common. Examples of use include the Littletons, just north of Evesham, Croome Court’s follies and outbuildings and several walls and bridges in Worcester.
Coarse conglomerates and red sandstones with rounded pebbles of quartz and other lithologies. Likely used in some buildings in Goodrich although difficult to distinguish from a similar layer in the Brownstones which outcrops in Goodrich Castle moat. Also used in some local buildings on Penyard Hill above Ross. Notable use was made of the Quartz Conglomerate to produce millstones in the Forest of Dean around Redbrook. From a site above the Wye these were exported by river and may have supplied cider mills as far away as Bredon Hill.