Metalworking

Evidence for iron and copper working is scarce, especially for the Iron Age; but developer-funded fieldwork has provided some examples. At Gunhills, Armthorpe, a hearth with evidence for high temperatures produced a radiocarbon date of 166 BC–AD 132, and was associated with handmade, grog-tempered pottery; whilst an excavated oven produced an archaeomagnetic date of 95 BC–AD 80 (Richardson 2008: 9-10). Though the high temperatures hint at metallurgical processes, there was no slag or hammerscale directly associated with those features, although there was elsewhere. Iron working and copper-alloy working residues were recovered from the ring ditch or eavesdrip gully of a roundhouse at Carr Lodge Farm, near Balby Carr and Loversall Carr south-west of Doncaster (Stanley and Langley 2013: 14), along with much charcoal, and fragments of triangular ceramic crucibles believed to be of Iron Age form and date. The iron-working slag included a small, rounded, part-complete smithing hearth bottom formed in the base of a smithing hearth (Mortimer 2013: 43-4). ‘Iron concretion’ was also recovered – possible bog iron? Several crucible fragments had traces of copper-alloy on them and fired clay and burnt stone was also found. At Engine Lane, Shafton, tap slag was associated with 1st century AD ceramics, and thus either late Iron Age or early Romano-British (Burgess 2003). Carr Lodge Farm and Engine Lane Shafton are unpublished. At Parrots Corner, Rossington Bridge, a roundhouse ring gully containing 1st century BC pottery also yielded a ceramic crucible fragment with copper-alloy residues, remains of two tuyères and iron hammerscale (Bishop 2010: 11).

At Deepwell Mews, Halfway, Sheffield, several pits produced hammerscale, charcoal, and Iron Age-style pottery (Wells 2018: 6). A lump of bog iron ore was also found in one pit, and early Romano-British pottery of 1st to 2nd century date in a few of these features too. There appears to have been continuity of occupation and ironworking at the site, and its location on quite a steep east-facing slope above the River Rother suggests the use of the updraught effect to achieve higher temperatures. At Billingley Drive, Thurnscoe, vesicular ferrous fragments of so-called ‘Iron Age Grey’ slags were identified, these almost always associated with late Iron Age sites (Cowgill 2004b: 54). The ditch section they were from was dated to the 2nd century AD by a single pottery sherd, so either indicates earlier Iron Age activity, or the persistence of metal working techniques into the Roman period. Iron block and tap slags at Armthorpe were predominantly from smelting (Cowgill 2008: 48), along with vitrified clay from furnace structures, and smithing slag and hammerscale. The two different types of smelting slag are rarely found together, with block slags usually considered to be mid to late Iron Age in date; and this may indicate a transitional technology. A clay crucible was found in a ditch on another part of the West Moor Park Armthorpe site, along with smithing slag, cinder and fuel ash slag (Hughes 2006: 13).

Iron-working evidence such as slag or vitrified hearth lining has also been found at Smarson Hill Plantation, South Anston (Radley and Plant 1969); Doncaster Park and Ride, Scawthorpe (Bishop 2005); and Ashfields, Stainforth (Dransfield and Harvey 2012: 5, 10), though all these examples may be of earlier Romano-British date. At Rossington Grange Farm, a ditch contained a spill of leaded tin bronze with a high tin content and some silver, possibly an alloy of Iron Age rather than Roman date (McDonnell 2016: 27). The ditch also contained Roman pottery of mid to late 3rd century date, however, and although it is unclear if these ceramics were from a tertiary fill (Roberts and Weston 2016: 17), it seems more likely that the alloy was of Roman date too. Further evidence for more specialist metalworking was found on a clay crucible excavated in a 2nd century pit at St Sepulchre Gate in Doncaster, which had traces of silver (Bailey 1986: 196, fig. 43); and litharge from another Doncaster pit of similar date at Frenchgate, this being a waste product associated with the recovery of silver from lead, perhaps from coins (Tylecote 1986: 196). A probable smithy, clay crucibles and iron slag were found within a walled area of the vicus at Templeborough (May 1922: 56-9), along with cisterns perhaps used for quenching.

There is more evidence of metalworking following the Roman occupation, though outside of military sites the ways in which this was undertaken and organised are still unclear. Iron objects became more common on small-scale rural sites, especially nails and metal fittings of various sorts; but so too does evidence for metalworking itself. An ore roasting furnace was found near Thorpe Audlin (Houlder and Hedges 1982). Smelting as well as smithing was suggested at Manor Farm, Bessacarr (MAP 2014). Iron smelting tap slag and hearth bottom smithing slag was both found at Rossington Grange Farm (McDonnell 2016: 26). Smithing slags, ferrous slag bottoms, furnace lining and hammerscale were recovered from Billingley Drive, Thurnscoe and Ashfields, Stainforth (Cowgill 2004b; Wessex Archaeology 2012). At Holme Hall Quarry, the iron slag found indicated smithing rather than smelting, predominantly during the 3rd century AD (MacKenzie 2007: 73-4); and parts of hearth bottom slags from small-scale smithing were also found at Pastures Road, Mexborough (Jones 2008). At Whirlow Hall Farm, Roman lead and pewter working was indicated by lead waste and portable XRF geochemical analyses (Doonan 2017; Doonan and Slater 2017). A fragment of ferrous smithing hearth bottom was also recovered from the enclosure ditch (Lortie and Doonan 2017: 89).

Several other aspects of metalworking are noteworthy. Near the Romano-British pottery kilns excavated at Cantley an iron smelting furnace or bloomery was also excavated, and this partly stone-built structure contained iron slag, ash, charcoal, and the lower part of a rotary ‘beehive’ quern with ferrous staining on its flat surface was built into the walling (Cregeen 1956: 35-9, figs. 3-4, plates i-ii). The feature was backfilled with dark soil that included a pig scapula and a bronze plate, and there were some lumps of clay and fired clay above it; but no dateable artefacts were recovered. It was proposed that the raw material was in part composed of bog iron (ibid.: 41). The furnace’s proximity to the pottery kilns may suggest shared ‘high temperature’ practices, possibly with some of the same people involved. The re-use of a quernstone for metalworking at Cantley is paralleled by examples elsewhere with heat reddening and/or ferruginous deposits indicating their possible re-use as anvils; as at Balby Carr and Roebuck Hill, Jump (Heslop 2005; Wright 2007: 54), Ferrybridge in West Yorkshire (Heslop and Gaunt 2005: 149), and Gamston and Ramsdale in Nottinghamshire (Garton, Southgate and Leary 2000: 40; Knight 1992: 72). This might indicate pragmatic re-use of hard, flat stone surfaces but could also suggest symbolic links between metalworking and agricultural production.

During the Iron Age, iron objects could have been produced from ironstone sources in the Cleveland Hills and local Coal Measures, or as bog iron, found as iron pan in river valleys and the Humberhead Levels (q.v. Crew 1991; Halkon 1997, 1999; Halkon and Millett 2000, 2003). The enclosure at Whirlow Hall Farm was close to a local iron source in the Limb Valley (Doonan 2017: 106). Bog iron was found at Deepwell Mews, and an iron concretion from Carr Lodge Farm might also be derived from bog iron. The copper ore source for copper-alloy objects found in South Yorkshire is unknown, but the nearest are Alderley Edge in Cheshire or Ecton Hill in north Staffordshire (P. Buckland pers. comm.). Although basic smithing probably took place at many settlements, just a few highly skilled individuals or households may have produced high-status iron and copper-alloy objects. Those most skilled at metalworking could have held considerable power, but perhaps ambiguous social status. One study of copper-alloy working found that from the 4th century BC through to the early 1st century AD alloys in northern Britain were mainly composed of tin bronze in consistent proportions suggesting smiths followed a ‘recipe’ (Dungworth 1996: 404). Arsenic was a frequent impurity, indicating smelting at relatively low temperatures. From the early 1st century AD, copper alloys had varying levels of zinc incorporated within them, this probably derived from imported Roman brass.

Knowledge of iron and copper working might have been restricted during the Iron Age, surrounded by rites and proscriptions. These practices and the resulting materials and objects themselves could have been entangled with symbolism and metaphors associated with fertility and reproduction (Aldhouse-Green 2002: 16; Budd and Taylor 1995: 139; Giles 2007c: 398-399; Hingley 1997a: 12; 2006: 217-8). Evidence of depositional practices from Roman Britain (see below) suggests that some such meanings survived beyond the Roman conquest. The Roman occupation and the presence of additional smiths associated with the military may have disrupted existing indigenous metalworking social and economic links though, whilst Roman supply networks facilitated the import of ores from a much wider geographic area, though the extent of this is still unclear. Tin from Cornwall, for example, would have been present at Whirlow Hall Farm for pewter production (Doonan 2017).

Research questions

  • How can we add to our existing knowledge of industries and crafts in this region, particularly the extraction and smelting of iron and lead? When was block slag technology replaced by tapped shaft furnaces (q.v. Cowgill 2008: 50), and was this later in South Yorkshire than other regions?
  • Can we identify potential sites and area of metalworking production more effectively? What was the extent and nature of the use of bog iron? Are there any traces of ore extraction surviving, or has it all been destroyed by medieval and post-medieval surface workings?
  • How can we better understand the exchange and deposition of metal artefacts?
  • How can we ensure adequate analysis and publication of artefacts, particularly those recorded under the Portable Antiquities Scheme? How well are pre-PAS metal-detecting finds recorded on the HER? Many in museum collections may not be documented;
  • Where have the Iron Age and earliest Roman metal artefacts and coins been found in South Yorkshire? Are there any spatial overlaps, and is there any evidence that these might have reflected pre-conquest contacts?
  • Can we identify other patterns of deposition of metalwork and other artefacts? Are there any correspondences in landscape associations for deposition? What roles did watery places, rock outcrops and other ‘natural’ locations perform regarding structured deposition, did some of these reflect ritualised practice, and how might these have changed over time?
  • Was there a late Iron Age ritualised site at Rossington Bridge, or was the material there disturbed/redeposited? Is any further investigation at the site possible, involving geophysics and/or targeted excavation?
  • How did patterns of Roman coin use and discard/deposition change over time? Were patterns of late Roman artefact and coin deposition different to earlier centuries for example? Outside of Doncaster and military bases, can we identify any settlements tied into a monetised economy? What were the social or economic mechanisms by which coinage penetrated the countryside?
  • How did individuals and communities identify and define themselves in South Yorkshire during the Iron Age and early Romano-British periods? Did metalwork play a role in this, and can any possible social groupings be identified? Could these indicate territoriality? Can we identify any status differences between Iron Age and Romano-British individuals and settlements? How were such variations manifested? Is there any evidence for such groupings persisting into the Romano-British period?

Priorities and implementation

  • Geophysical survey techniques such as magnetometry and magnetic susceptibility should be used to identify possible industrial features both before and during evaluations and excavations. Portable XRF (X-ray Fluorescence) equipment might also be useful in searching for areas of copper-alloy, lead and other metal concentrations (Doonan and Slater 2017; Frahm and Doonan 2013; Tighe 2018);
  • Magnets should be used as a matter of routine during sampling and/or sample processing in order to recover hammerscale. Any features associated with metalworking or suspected to be involve must be independently dated using radiocarbon and archaeomagnetic techniques;
  • Significant copper-alloy objects such as torcs, brooches and dress or harness fittings should be analysed using techniques such as Energy-dispersive X-ray spectroscopy (EDXRF) where possible, especially if their date is ambiguous. Detailed analyses and 3-D laser scanning of the Cadeby sword or dagger chape, the Dinnington torc, and the Cadeby hoard bracelets would be potentially productive, provided such work was published;
  • Links between detectorists, PAS Finds Liaison Officers and archaeologists must be maintained and encouraged through workshops and meetings;
  • At the same time, however, Scheduled and non-Scheduled enclosure sites should be the focus for gridded archaeological metal detecting surveys designed to remove and record metalwork artefacts in topsoil under controlled conditions, to prevent them being lost forever to illegal metal detectorists. The spatial distribution of artefacts can be plotted in detail;
  • A project run in conjunction with local archaeological societies and volunteers could survey possible prehistoric and Roman-period metal ore extraction sites. Though in many instances post-medieval and early modern workings will have destroyed evidence, traces might survive in wooded areas that have had tree cover since the medieval or post-medieval periods; or are on steep slopes and other more inaccessible areas that might nonetheless have proved attractive in the past. Predictive GIS-based work would help with this;
  • The landscape associations of metalwork objects in South Yorkshire could form the focus for MA research, or part of a PhD. Recent work on Iron Age and Romano-British coin hoards in England which included South Yorkshire as part of a regional case study, suggests that in some instances it was the aesthetic or social/symbolic significance of landscape locales that influenced depositional practices (Bland et al. forthcoming).
  • Unpublished excavations of sites with metal artefacts and/or metalworking evidence need to be fully published as a matter of urgency (see below).