CHAPTER II REGIONAL GEOLOGY by Graham K. Lott The ‘quarrying’ and use of local stone in Notting- the Triassic comprises a thick succession of non- hamshire, for both building and decorative purposes, marine, green-grey to reddish brown sandstones, dates back to Roman times. However, the lithological siltstones and mudstones, the latter including thinly units that characterise the geological succession interbedded, grey-green, dolomitic, very fine grained within the county contain only a few beds of stone sandstones (known locally as skerry). In contrast, the suitable for these purposes. This lack of indigenous early Jurassic marine succession is only sporadically stone useful for decorative carving is reflected in the exposed along the northern edge of the low-lying composition of the suite of carved stone fragments Vale of Belvoir and comprises a succession of grey that have been studied as part of this Corpus project. limestones and mudstones (Lias Group). The eastern By far the majority of the stones examined consist part of the county is locally blanketed by extensive of lithologies (primarily sandstones and limestones) tracts of glacial and alluvial sediments (unconsolidated sourced from outside the county border. sands, gravels, clays and muds) of Quaternary age. carboniferous THE GEOLOGY OF NOTTINGHAMSHIRE Pennine Coal Measures Group Nottinghamshire has a relatively simple geological The Carboniferous rocks that crop out in the west of succession comprising a sequence of eastwards- the county form part of the Pennine Coal Measures dipping sedimentary rock units whose outcrops Group. This succession is best known economically extend from north to south across the county (see for its coal reserves but also contains a number of Fig. 3 and Table 1). The geologically oldest beds are relatively thinly bedded, hard, fine-grained, quartzose of Upper Palaeozoic age and crop out in a narrow sandstone beds, some of which have been quarried strip along its south-western border. They comprise extensively for local building stone around, for the lithologically varied coal-bearing sandstone and example, Eastwood, Kimberley and Trowell. However, mudstone successions of the Pennine Coal Measures in general these sandstones are not suitable for carved Group (Upper Carboniferous) and form part of the stonework and have not been identified in the Corpus Derbyshire-Nottinghamshire Coalfield. These beds stones of the Nottinghamshire area. are overlain to the east by a thin, variegated sequence of orange-brown to pale yellow-coloured, dolomitic (or permian magnesian) limestones, and soft red-brown clays and sandstones of Permian age. Together these geological Zechstein Group units form the higher ground that characterises the The overlying Permian succession in the western part county’s western border extending from the sandstone of the county can be subdivided into a lower unit of cliffs of Nottingham Castle in the south to Gringley dolomitic limestone (the Cadeby Formation) and an on the Hill in the north. upper interval in which red clays (often termed marls) Continuing eastwards across the county the Permian and sandstones dominate (the Edlington Format- succession is succeeded by a thick Triassic and early ion). The Cadeby Formation, formerly known as the Jurassic (Mesozoic) sequence which underlies the Lower Magnesian Limestone, is the source of Nott- remainder of the county. Typically in Nottinghamshire inghamshire’s best-known building and decorative 11 N 12 CHAPTER II N Retford Worksop Retford Worksop Mansfield Sutton In Ashfield Southwell Mansfield Newark On Trent Hucknall Sutton In Ashfield Eastwood Southwell Carlton Newark On Trent Hucknall Nottingham Eastwood Beeston Carlton Nottingham Beeston 0 5 10 Km 0 5 10 Km Nottinghamshire Bedrock Geology Bedrock Geology LIAS GROUP - MUDSTONE, SILTSTONE, LIMESTONE AND SANDSTONE NottinghamshiTRIASSIC ROCKSre Bed (UNDIFFERENTIrock GeologyATED) - MUDSTONE, SILTSTONE AND SANDSTONE TRIASSIC ROCKS (UNDIFFERENTIATED) - SANDSTONE AND CONGLOMERATE, INTERBEDDED Bedrock Geology PERMIAN ROCKS (UNDIFFERENTIATED) - SANDSTONE AND CONGLOMERATE, INTERBEDDED LIAS GROUP - MUDSTONE, SILTSTONE, LIMESTONE AND SANDSTONE PERMIAN ROCKS (UNDIFFERENTIATED) - MUDSTONE, SILTSTONE AND SANDSTONE ZECHSTEINTRIASSIC ROCKS GROU (UNDIFFERENTIP - DOLOMITISEDATED) LIMES - MUDSTONET ANDONE, DOLOMITE SILTSTONE AND SANDSTONE PENNINETRIASSIC MIDDLEROCKS (UNDIFFERENTI COAL MEASURESATED) FORM - SANDSATIONT ANDONE SOUTHAND CONGLOMER WALES MIDDLEATE, INTERBEDDEDCOAL MEASURES FORMATION (UNDIFFERENTIATED) PENNINEPERMIAN LOWERROCKS COA(UNDIFFERENTIL MEASURESATED) FORM - SANDSATION TANDONE SOUTH AND CONGLOMER WALES LOWERATE, COA INTERBEDDEDL MEASURES FORMATION (UNDIFFERENTIATED) PERMIAN ROCKS (UNDIFFERENTIATED) - MUDSTONE, SILTSTONE AND SANDSTONE ZECHSTEIN GROUP - DOLOMITISED LIMESFIGURETONE AND DOLOMITE3 PENNINE MIDDLENottinghamshire COAL MEASURES FORMATION bedrock AND SOUTH WgeologyALES MIDDLE COAL MEASURES FORMATION (UNDIFFERENTIATED) PENNINE LOWER COAL MEASURES FORMATION AND SOUTH WALES LOWER COAL MEASURES FORMATION (UNDIFFERENTIATED) REGIONAL GEOLOGY 13 TABLE 1 Stratigraphical divisions in Nottinghamshire Geological Period Principal sculptural Rock Type stone units Jurassic (Middle) Inferior Oolite Group (not at outcrop in Nottinghamshire) present as imported stones ooidal and bioclastic Lincolnshire Limestone Formation limestone Jurassic (Lower) Lias Group none Triassic Penarth Group Mercia Mudstone Group mudstone-dominated (includes ‘Skerry Sandstone’) present Sherwood Sandstone Group (sandstone-dominated) Permian Zechstein Group Brotherton Formation (Upper Magnesian Limestone) none dolomitic limestone Edlington Formation none Cadeby Formation (Lower Magnesian Limestone) present sandy dolomitic limestone Marl Slate none Basal Permian Sand none Carboniferous Westphalian Pennine Coal Measures Group Pennine Upper Coal Measures Formation none Pennine Middle Coal Measures Formation none Pennine Lower Coal measures Formation none Namurian Millstone Grit Group (not at outcrop in Nottinghamshire) present as imported stones sandstone, quartzose 14 CHAPTER II stones. These limestones were quarried extensively in façade, which have suffered badly from the effects of the past for building stone at Bulwell, Linby and in the nineteenth-century pollution. Numerous medieval Mansfield area. parish churches in this north-western area of the county The Bulwell-Linby stones are distinctive, both com- have also used these Cadeby Formation limestones prising yellow-brown to orange, coarsely crystalline, for much of their ashlar walling and sometimes for sandy, dolomitic limestone lithologies. They form elaborately carved stonework, for example in the thinly-bedded successions in both these locations, twelfth century at Edwinstowe, and Blyth in the later with individual limestone beds averaging 15–20 cm eleventh. The Mansfield quarries continued to supply and only rarely reaching thicknesses greater than 30 high-quality stone for ashlar and carved decorative cm. Both stones were widely used in the past for stonework until quite recently. However, despite their local construction, particularly in the nineteenth- and obvious local importance and their long history of use, early twentieth-century suburban developments of stone from these quarries has not been identified among Nottingham. Evidence of the use of Bulwell Stone the Corpus stones examined in Nottinghamshire. is widespread, well documented as far back as the Further north, along the western county border sixteenth century by its common occurrence as large with Derbyshire, quarrying of the Cadeby Formation grave-stone slabs and in chest tombs of the period. limestones was also intensive in the past, notably The very extensive, former quarry sites found around Steetley. Here the dolomitic limestone lithol- around Linby in medieval times supplied stone for ogies change to almost pure white, fine-grained, Newstead Abbey and are still operational on a small ooidal and occasionally peloidal, varieties with no scale today. As with the Bulwell limestone the thinly- quartz sand content evident. Again the limestones bedded nature of these limestones, and their coarsely are seen in numerous older local buildings between crystalline character, has meant that they have only Mansfield (Mansfield Woodhouse Stone) and Work- occasionally been used as a source of block-stone sop (Steetley Stone). At Carlton-in-Lindrick, the suitable for carved stonework. However, the evidence church with an early Norman tower provides testa- provided by the early carved stone panel now built ment to the early use of the local pale dolomitic in over the doorway at Papplewick church (p. 131, limestones and their evident suitability for building Ills. 63–7) suggests they could sometimes be used for and decorative stonework. A single carved Corpus decorative work. fragment, reused in the external fabric of its chancel, Further north, around Mansfield the dolomitic was examined and was probably also sourced from the limestones of the Cadeby Formation change quite local Cadeby Formation succession (p. 94). A group dramatically in character, becoming finer grained of rather standard ‘overlap’ grave-covers examined at and pale yellow and white in colour. At Mansfield Blyth, Halloughton and Mattersey Priory also employ the formation includes two relatively thickly-bedded, this stone type (Appendix A, pp. 199, 202, 203). sandy dolomitic limestone varieties known locally as The Permian (Cadeby Formation) white dolomitic the Red and