Roman, Mediaeval and Post-Mediaeval Metalworking Debris at ...

Roman, Mediaeval and Post-Mediaeval metalworking debris | Specialist collections assessment 2012 Gerry Mcdonnell Archaeometals

Dr Gerry Mcdonnell, Gerry Mcdonnell archaeometals, January 2012 1

Contents

Section Heading Sub-Heading Page

1 Introduction 1

2 Methodology 2

3 Slag Classification 5

4 Results 7

4.1 Devon Archaeology: pre-1940 7

4.2 Devon Archaeology 1945-1969 7



4.5 Devon Archaeology Undated 21

4.6 Exeter Archaeology 1945-1969 24



5 Discussion 40

6 Recommendations 42

7 Conclusions 44

References 44

Appendix 1 Details of spreadsheets 46

Appendix 2 Pomeroy Wood, X-radiographs with possible hammer scale

48

1. Introduction:

The aim of the assessment was to rank the assessed metalworking debris according to the following

criteria.

(i) Provenance and history (resulting in ranking of importance in terms of international, national, local,

regional, community/group).

ii) Representativeness and best examples of type (locally, regionally, internationally,

community/group)



iii) Importance to the study or development of archaeology and history in the UK, internationally, and

in particular in Exeter and Devon

Furthermore to categorise the assessed metalworking debris into:

i) Material which offers a high research potential

ii) Material which is unlikely to yield much useful information.

The museum holds 367 boxes of material that could be considered to contain metalworking debris.

Some boxes only contained metalworking debris, whilst other boxes contained a variety of material

types, in some cases with only one small bag of slag. The museum identified a proportion of the

archive to be assessed (Table 1), but due to the help provided it was possible to make an assessment

of all the material in the archive, with the proviso that not all the boxes of copper alloy casting mould

were examined. In addition an extensive programme of non-destructive X-ray Fluorescence (XRF)

analysis was undertaken.

Locality Excavation Dates Number of boxes

Exeter Archaeology 1945-1969 4

Exeter Archaeology 1990-2012 28

Devon Archaeology pre-1940 4

Devon Archaeology 1945-1969 5



Social and Industrial History 1

Table 1 Number of boxes by locality and date that were identified for assessment (Total 130 Boxes).

2. Methodology:

The basis of the examination was visual identification of the material. Some level of quantification

was also provided, but as the assessment progressed, the bags were either weighed on scales or for

large heavy boxes of material, the weight was estimated. Hence, there is a discrepancy in data detail

between the material examined in the initial stages and that examined in the latter part of the

assessment. The material in the bags were not examined in great detail, and so the dominant type

of slag in a bag was identified, for example a bag containing smithing slag lumps may also contain



pieces of hearth lining etc. Large bags containing smithing debris were checked with a magnet to

assess the presence or absence of hammer scale. The data was entered into an Excel spreadsheet,

and the data manipulated to generate an overview of each site details of spreadsheets are given in

Appendix 1. The sites are discussed in Section 4, Results, and a summary of the site, including

material significance and research potential is provided. The assessment of national or regional

significance depended on a number of factors. These included:

Bronze Age

Metalworking activity is automatically of regional and national significance.

Iron Age

Non-ferrous smelting – regional and national importance

Non-ferrous smithing e.g. casting, - regional significance, but could be national if significant mould

fragments survive

Iron smelting regional and national significant

Iron smithing – if the assemblage is complete, and by this it contains most of the smithing diagnostic

residues in quantity, then it is of regional and national importance. If its partial or in small quantity

then it is of regional significance.

However iron objects rarely survive on Iron Age sites, so the recovery of iron smithing debris is the

best indicator of consumption of iron on Iron Age sites, i.e. does a greater quantity of smithing activity

occur on larger/higher status sites etc.

Roman Period


Non-ferrous smithing e.g. casting, - if in significant range and quantity, regional significance, but

could be national if in large quantities and securely dated.

Iron smelting - regional significance if full assemblage present. If the morphology is typical of Iron

Age smelting as opposed to the classic Roman ‘tap slag’ then the date could be significant and the

assemblage could rise to national importance.

Iron smithing – if the assemblage is complete, and in in quantity, then it is of regional importance. A

complete smithy, with building evidence would be of national significance.

Early Medieval, Medieval and Post-medieval Periods




Non-ferrous smithing e.g. casting, - if in significant range and quantity, regional significance, but

could be national if in large quantities and securely dated.

Iron smelting - regional significance if significant parts of the assemblage are present. If the

assemblage was complete and large then the assemblage would rise to national importance.

Iron smithing – if the assemblage is complete, and in quantity, then it is of regional importance. A

complete smithy, with building evidence would be of national significance.

The research potential reflects the regional and national importance. The research potential

(high/low) was assessed both in terms of archaeometallurgical criteria (see Bayley et al. 2008) and

the archaeological data where available. The research potential may apply to the

archaeometallurgical material or to the landscape.

The assessment of the relevance of an assemblage to Community/Group Significance is harder to

assess. This field was not commented upon, but those with research potential could be steered to

relevant groups.

The material on display in the gallery was recorded separately, but is commented on if relevant in the

site summaries. One box (EX 3141) contained one or more bags of material from 18 sites. These

make no change to the overall interpretation or status of those sites. This material could either be re-

boxed to the correct box or disposed of.

XRF Methodology

The instrument is a Bruker S1 Turbosdr hand-held XRF instrument operating at 40kV. A beam of x-

rays is generated in the instrument and focussed on the sample, the x-rays interact with the

elements present in the sample resulting in the emission of secondary x-rays which are characteristic

(in terms of their energy and wavelength) of the elements present in the sample. The energy of the

secondary x-rays are measured and a spectrum generated showing a level of background noise with

peaks of the elements present superimposed on the background noise. Samples will analysed for 30

live seconds, the spectrum is stored and a normalised composition determined using a bespoke

Bruker Fundamental Parameters Programme (R-Alloys FP). All elements heavier than calcium (Ca,

Z=20), can be detected. The calculated two-sigma error on each element is calculated and overall

show values of the order of +/- 0.2%. The data is normalised and hence gives data showing relative

percentage of detected elements, clearly the dominant elements in a crucible fragment are oxygen,

aluminium and silicon which are not detected. The data is generated in a comma delimited file and

then exported to an Excel spreadsheet, where the data is examined and relevant tables generated.

The technique is non-destructive.



3 Slag classification:

The material was visually examined and the classification is based solely on morphology. In general

metalworking and other debris are divided into THREE broad groups. First are the diagnostic ferrous

material which can be attributed to a particular industrial process; these comprise ores and the

ironworking slags, i.e. smelting and smithing slags. The second group, are the diagnostic non-ferrous

slags which can be attributed to a particular industrial process; these comprise the crucibles, moulds,

metal spills etc. Thirdly, the non-diagnostic slags, could have been generated by a number of

different processes but show no diagnostic characteristic that can identify the process. In many cases

the non-diagnostic residues, e.g. hearth or furnace lining, may be ascribed to a particular process

through archaeological association. The residue classifications are defined below.

3.1. Diagnostic ferrous slags and residues:

Ore - Iron rich natural mineral, may be identifiable to a particular type e.g. Goethite or hematite

Tap Slag - this smelting slag is characterised by its ropey flowed morphology, indicating a free

flowing slag. The slag is normally black in colour. The upper surface is smooth, sometimes with

ripples. Large gas bubbles may occur.

Smelting Slag - this smelting slag is characterised by its viscous appearance (compared with the

relative free flowing morphology of smelting tap slags), and often the presence of large charcoal

impressions (approximately 25 mm in square section and at least 30 mm long).

Smithing Slag - randomly shaped pieces of iron silicate slag generated by the smithing process. In

general slag is described as smithing slag unless there is good evidence to indicate that it derived

from the smelting process.

Hearth Bottom - a plano-convex accumulation of iron silicate slag formed in the smithing hearth.

Metal – metallic iron fragments, that lack a distinctive morphology of an artefact and may be

fragments e.g. of bloom, the raw metal extracted from the furnace.

Hammer Scale - there are two forms of hammer scale, flake and spheroidal. During heating a piece

of iron may develop a thin skin of scale, which is predominantly iron oxide. This will break from the

metal during hammering, and normally falls to the ground as small (usually less than 5 mm long)

fishscale - like flakes. During fire welding, the mechanical joining of two pieces of metal at high

temperature, the surfaces to be joined will have been cleaned by the addition of a flux (usually sand).



The flux reacts with any scale present to form a thin film of liquid slag. When the pieces are

hammered together the slag is expelled, and during flight forms balls of liquid slag (<10 mm diameter)

and freeze. Both these micro—slags are generated during smithing, and are normally deposited

around the working area (around the anvil). The presence of hammer scale is therefore a strong

indicator that smithing (primary or secondary) was carried out on the site. Their small size precludes

their hand recovery, and they are usually recovered during soil sample sieving (for environmental

data). They are therefore not recorded in the context by context listing of the slags, but are noted

when present.

Cinder - high silica content smithing slag, often formed at the reaction zone between the smithing

slag and the hearth lining.

3.2 Diagnostic non-ferrous slags and residues:

Native Metal – naturally occurring metal, metals normally occur as minerals, e.g. oxides, sulphides

etc. In certain circumstances the metal occurs in the metallic form .

Ore – ores of copper, tin, lead and other non-ferrous metals.

Crucible – ceramic vessels in which the metal or alloy was melted.

Mould - the shape usually made of clay, sane or stone into which the metal or alloy is poured

Cupellation and Parting– special processes to extract silver from base metals (e.g. lead or copper -

cupellation). Separation of gold from silver (parting).

Slags with non-ferrous corrosion – slag formed either in hearths or from other material with copper

alloy corrosion (green).

Metal Spills – frozen spills of molten metal.

Scrap – broken fragments of metal.

3.3 Non-diagnostic slags and residues: Hearth or Furnace Lining - the clay lining of an industrial hearth, furnace or kiln that has a vitrified or

slag-attacked face. It is not possible to distinguish between furnace and hearth lining. Many of the

lining fragments were attacked by slag and some were grey in colour.

Cinder - high silica-content slag that can either be formed as described above or by high

temperature reaction between silica and ferruginous material. It can be considered either a non—

diagnostic slag or a diagnostic slag depending on its iron content and morphology.



Other Material comprised possible, ferruginous concretions (probably naturally formed iron rich

precipitates, although they may have formed after the archaeological deposits), fragments of fired

clay, charcoal fragments and burnt stone.

4 Results

4.1 Devon Archaeology: pre-1940

4.1.1 Hembury (1934, 1935 and 1980-83)

Evidence – copper alloy casting mould fragments (XRF 457, no copper alloy elements detected at

significant levels), also iron smelting slag (Iron Age) iron ore, and possible SSL fragments. Note

Todd (2007) states a fabrica was present in the Roman Fort constructed on the site.

National Significance - Yes

Regional Significance - Yes

Community/Group Significance -

Research Potential - Yes

Retention Advice - 100%.

4.1.2 Holcombe Villa (pre- 1940) and 1969-75

Evidence – c. 4kg of smithing debris, and copper ingot (XRF 468, leaded brass with minor tin levels)

and crucible or mould fragment (XRF 469, cooper, zinc, tin, antimony and lead were detected)).

Blacksmithing tools including tongs are on display in the gallery (Gallery LR62-70).

National Significance - No







4.2 Devon Archaeology 1945-1969:

4.2.1 Blackbury Castle (1952-54)

Evidence – small quantity of iron smithing slag


Regional Significance - No


Research Potential - No, though smithing is the most important craft in medieval castles.

Retention Advice – 100%, evidence of smithing in the castle.

4.2.2 Dean Moor (1954-56)

Evidence – iron ore (1kg) and iron smelting slag (0.3kg), whetstones also found. Cassiterite nodule.

A sample of slag was on display in the Gallery (Gallery LP41) and described as tin slag, but XRF

analysis (XRF 443 and 444) showed the slag to be iron slag.





Retention Advice – 100%.

4.2.3 Kes Tor 1951-52

Evidence – iron smelting slag (Iron Age. One sample has been cut and a thick section removed by PC

Peter Crew?), and refers to a report on page 59, but no details of publication. Two large soil samples

E quarter Pound Hut furnace soil sample checked for hammer scale none, lots of magnetic material.

Sample of 1mm sieve also had a high magnetic fraction, no hammer scale. One piece of cassiterite

confirmed by original Kes Tor report and XRF analysis (XRF 466).







Retention Advice – 100%, could reduce soil sample if analysed for environmental evidence.

4.2.4 Seaton Villa (1969)

Evidence – small amount of iron smithing slag debris, some hearth lining and a lead spill. One iron

artefact that should be placed in stable storage.




Research Potential - No

Retention Advice – 100%, evidence of smithing activity at the villa.

4.3 Devon Archaeology 1970-1989

4.3.1 Berry Meadow Kingsteignton (1985)

Evidence – smithing debris including a high iron content hearth bottom that requires stable storage.





Retention Advice – 100%, until context understood.

4.3.2 Buckfast Abbey (1980-1990)

Evidence – Over 20kg of smithing debris, smithing area marked on site plan, but these look like pits.

Slag sent to AML but no report. Also c 8kg smithing debris from Southgate excavation (1991).

National Significance – Yes largest quantity of smithing debris from a Cistercian Abbey in Britain.







4.3.3 Bury Baron (watching brief 1984-85)

Evidence – Non-Diagnostic Cinder





Retention Advice – Discard.

4.3.4 Chicacott, Oakhampton Fort (1st century) (1976-1977)

Evidence – Non-Diagnostic Cinder





Retention Advice - Discard.

4.3.5 Crediton (1986)

Evidence – not slag corroded iron objects, but not in stable storage.





Retention Advice – If regarded as a significant iron object then place in stable storage, if not discard.

4.3.6 Crediton Hayward’s School 2002

Evidence – 2 fragments of post-medieval smithing slag and corroded iron objects, but not in stable

storage.








4.3.7 Dainton 1975

Evidence – Bronze Age casting debris see Nedham et al (1980). The assemblage includes circa 13

soil samples, visually there is no evidence of copper alloy staining. Analysis (XRF 492) of one topsoil

sample (0-10cm depth) detected no copper but some zinc. Analysis (XRF 493) of sample 414-114 (8-

20cm depth) detected copper and zinc, (note zinc may derive from the plastic bag) . XRF screening

of all soil samples could reduce the volume of samples significantly. A mould fragment was

analysed (XRF 470-472), detected copper, zinc and tin as major elements.


Regional Significance -Yes



Retention Advice – Retain all moulds etc., check all soil samples for metallurgy (XRF) and

environmental evidence.

4.3.8 Exmouth (1982-84)

Evidence – smithing slag debris, and a copper alloy ingot (XRF 494) with a copper/antimony/tin/lead

alloy of similar composition to the alloys used in the cauldron casting at Cowick Street (Dungworth in

Blaylock 2000).


Regional Significance – Yes for the ingot



Retention Advice - re-assess after review of smithing activity across town.



4.3.9 Hayes Farm, Clyst Honiton (1987) Evidence – not metallurgical, burnt material






4.3.10 Hayne Farm, Uffculme ( ? )

Evidence – 2 lumps of iron tap slag



Community/Group Significance - Yes

Research Potential - Yes, if evidence of an ironworking site, check HER.


4.3.11 Lower Netherton (1989)

Evidence – dribble of tapped iron smelting slag (XRF 495).


Regional Significance – Yes, if dated


Research Potential - Yes if dated


4.3.12 Newton Abbot (1976, 1980-81, 1983)

Evidence – c. 18kg of smithing debris






Research Potential - Yes, to synthesise data from all 3 sites

Retention Advice - re-asses after review of smithing activity across the town.

4.3.13 Otterton Point (1989)

Evidence – fragment of hearth lining, during field-walking recovered one fragment smithing slag



Community/Group Significance - No



4.3.14 Overand, Thorverton (1984)

Evidence – iron smelting slag and lining, but on roadway, hence may be being used as hard-core, but

site will be near-by.


Regional Significance –Yes, if smelting site could be located.

Community/Group Significance - yes

Research Potential – Yes, fieldwork to locate site.

Retention Advice – 100% until site is defined.

4.3.15 Tiverton (1973-1974)

Evidence – classic tap slag, adjacent to river, water-powered? (1973), frags of SSL (1974)




Research Potential - Yes, possibly water-powered

Retention Advice - 100% until site is defined.

4.3.16 Totnes 39 Fore Street (1982)

Evidence – 5 fragments of smithing slag







Retention Advice – Needs further information.

4.4 Devon Archaeology 1990-2012

4.4.1 A30 Excavation (1996-9) A series of excavations along the A30 Honiton to Exeter improvement scheme were excavated

between 1996-9 and were published in 1999 (Fitzpatrick et al 1999). The slags were reported on but

no detailed analyses were undertaken. Field-walking in 1994 prior to the development recovered

some slags including iron smelting tap slag. The sites are summarised in Table 2. The Black Horse

site produced some smelting slag probably dating to the Iron Age. This indicates, as has been

observed in other parts of the country that Iron Age societies exploited low lying bog ores as the main

ore source. Hence the site is of Regional Significance as an indicator of the location of the Iron Age

smelting industry. Pomeroy Wood produced extensive evidence for iron smithing, in excess of 10kg

of smithing debris including smithing slag lumps (SSL), hearth bottoms (HB) and hearth lining. The

material was reported by Phil Andrews (Andrews 1999) but a cursory re-examination of the material

and reading the report suggests that the excavation encountered a smithy which was not recognised.

Some bags were tested for hammer-scale, but as the slag appears to have been washed, none was

recovered. The X-radiographs of the iron objects recovered from Pomeroy Wood held at the County

Archive Offices were examined and features, probably entrapped hammers-scale were observed in

the corrosion products of some items (details provided in Appendix 2). It was also noted that some

radiographs may show the presence of copper alloy debris. Furthermore, cursory examination of the

report on the iron objects shows a marked increase in the number of objects in Phase 4i and 4ii in

which the majority of the slag was recovered. It is also significant that the majority of bar and rod

shaped items and unidentified items occurred in the same phases. Also two whetstones (context

4650, 4952, box DEV 1213) both fine-grained, both large size were recovered. These data strongly

indicate that a smithy was excavated or very close to the areas excavated. There was no programme

for the recovery of hammerscale during the excavation or during the examination of the large number

of environmental samples processed. In one case the environmental record indicates that it was

taken to recover hammerscale but there is no record as to whether it was recognised (Feature 4123,

Context 4130, Sample 1777, File 57, Archive box 56). The site lies in the valley below the Blackdown

Hills the site of a major Roman iron industry and hence is of major significance in researching the



Roman ironworking landscape. The Pomeroy Wood industrial residues and ironwork deserve further

research.

Retention – as a broad sweep through Devon, all material should be retained, until sites are

reviewed.



Site Period Material

Type

National

Significance

Regional

Significance

Research

Black

Horse

Iron Age Iron

Smelting &

Smithing

N Y Y

Castle Hill ? Iron

smelting

N N N

Fair Oak ? Non-

diagnostic

N N N

Gittisham

Forge

? Iron

smithing

N Y? Y?

Haynes

Lane

? Iron

smithing

N N N

Long

Range

? Iron

smithing

N N N

Pomeroy

Wood

Roman Iron

Smithing

Y Y Y

Table 2 Summary of the A30 Sites

4.4.2 Ash Farm, Ottery St Mary (1993)

Evidence – copper ingot s (XRF 464 and 465), both copper, and spill of lead, plus ingot of lead

National Significance - Yes, if date could be established

Regional Significance – Yes, if date could be established






4.4.3 Beer Head (1991)

Evidence – hematite iron ore, iron working slag, some is smithing some could be smelting.


Regional Significance – Depends on the date of the slag and if it is smelting slag


Research Potential - Requires research to resolve the slag type


4.4.4 Bolham Roman Fort near Tiverton (1993?)

Evidence – Iron Age iron smelting slag. Reported on by Budd in Maxfield (1991, 86-9). Report lacks a

context listing of the material, unless in archive. Deserves reconsideration in light of current

knowledge.

National Significance – Yes, IA smelting



Research Potential - Yes for overviews of IA iron production


4.4.5 Bridestow (1990-2012)

Evidence – copper ingot (XRF 461)






4.4.6 Church Field Alfington (1990)

Evidence – iron tap smelting slag




Regional Significance -Yes




4.4.7 Crib House, Membury (Blackdown Hills) (1993)

Evidence – Blackdown Hills iron ore, i.e. natural – recommend disposal, with the exception of piece in

bag labelled tithe apportionment no. 293/4 a ropey back vitreous slag which analyses (XRF 474-5),

detected copper and zinc.





Retention Advice – disposal of iron ore, retain vitreous slag. The ore should be utilised in reference

collection and teaching collections.

4.4.8 Cullompton (Roman Fort) (1992)

Evidence – small lump of smithing slag and a haematite nodule





Retention Advice – 100% as reminder of importance of smithing in a Roman Fort.

4.4.9 Dunkeswell Abbey (2000?)

Evidence – bog ore and one piece of iron smelting slag


Regional Significance – Yes if smelting slag can be phased




Research Potential - Yes, if there is more material

Retention Advice – 100% until points above resolved.

4.4.10 Gaffers Farm (Haycroft Farm), Membury (2000-2001)

Evidence – modern clinker, probably from firebox or cooking range





Retention Advice – 100% for reference collection/teaching collection.

4.4.11 Hemyock ( ? )

Evidence – classic iron tap slag


Regional Significance – Yes,



Retention Advice – 100%

4.4.13 Raddon Hill (1994)

Evidence – ironworking slag, possibly smelting, check Gent and Quinnell 2000.

National Significance – Yes the slag in Context Pit 781, if dated to c. 800-400 Bc is some of the

earliest in Britain if iron smelting slag and is early (Gent and Quinnell 2000, p21 last few lines)



Research Potential - Yes, if not done in detail in publication




4.4.13 Stockland (Fieldwalking near Blackdown hills) ( ? ) Evidence – medieval iron smelting tap slag, and iron ore, plus a piece of copper ore (XRF 473)

which confirmed the identification.


Regional Significance – Yes, for both finds


Research Potential - Yes, e.g. geophysics


4.4.14 Torbay (1990-2012) Evidence – two ingots (XRF 460-462), one copper , one copper arsenic.


Regional Significance – Yes.


Research Potential - Yes, if dating could be secured, arsenic suggest BA


4.4.15 Totnes Castle (1999)

Evidence – six small fragments of smithing slag from a watching brief. Smithing is the most important

craft in medieval castles.





Retention Advice – 100% as evidence of smithing in castles.

4.4.16 Totnes Fire (1991) Evidence – one fragment of smithing slag








4.4.17 Wolborough Street West, NCP Car Park, Newton Abbot (2005)

Evidence – no metallurgical material






4.4.18 Woodbury Great Close, Axminster (1990)

Evidence –smithing slag debris including a piece of hearth lining with arc of blow hole .





Retention Advice – 100%, the only blow hole so keep for reference collection.

4.5 Devon Archaeology – undated

4.5.1 Bigbury Bay

Evidence – tin ingots on display in the gallery (Gallery EP157 and EP158), one h-shaped ingot

(EP158) was analysed (XRF435) and shown to be pure tin.








4.5.2 Drewsteignton

Evidence – palstave (Gallery EP137), analysed (XRF 436)

National Significance – Yes





4.5.3 Escott House

Evidence – Bronze Age Hoard, (XRF 508 and 509), both analyses showed very high tin levels

indicative of either corrosion effects or that the original surface was tinned.






4.5.4 Gitisham Barrow 3

Evidence – 4 copper alloy ingots (LP6), analysed (XRF439 – 442), one was arsenical copper (LP6-1),

whilst two others were copper.








4.5.5 Morchard Bishop

Evidence – ingot on display in gallery (Gallery EP156), analysed (XRF434) showed it to be copper






4.5.6 Talaton

Evidence – a copper alloy scrap hoards (EP124), analysed (XRF 437 and 438) showing the

fragments to be copper.






4.5.7 Washfield

Evidence – worked copper alloy sheet, showing stress cracking of hammering would then be

annealed (Gallery LP29), analysis (XRF445) identified the alloy as tin bronze.








4.6 Exeter Archaeology 1945-1969

4.6.1 Banfylde House (1945-47)

Evidence –smithing debris





Retention Advice – 100% Historical significance.

4.6.2 Bartholomew Street East (1959)

See Exeter Archaeology 1970-1989.

4.6.3 Bedford Street (1945-47)

Evidence – kiln furniture





Retention Advice – not metallurgical.

4.6.5 DAES 1930

Evidence –thought to be a crucible, but XRF (XRF 448) detected no non-ferrous metals, therefore not

a crucible or mould.







Retention Advice - 100% Historical significance.

4.6.5 Exeter (1945-47)

Evidence – crucible (XRF 452) detected minor zinc, an object described as a stone mould but XRF

(XRF 452, 453 and 454) showed higher copper trace on exterior, possibly a pivot base.






4.6.6 Exeter locality unknown ( ? )

Evidence – crucible (XRF 449), minor trace of copper, zinc and lead were detected.






4.6.7 Gaters (1945-47)

Evidence – Non-diagnostic cinder







Retention Advice - 100% Historical significance.

4.6.8 South Gate (1964, 1965, & 1968)

Evidence – fragment of hearth lining, iron object, soil sample from a feature described as “furnace

under rampart”. Checked for hammerscale, none recovered, but significant magnetic content from

burning. 1 heavily corroded obj in 2 parts.





Retention Advice - 100% Historical significance?

4.6.9 St Georges (1945-47)

Evidence – location description "soil sample under gravel debris from Cu alloy working", potential

remnants of working floor, droplets of Cu alloy. Analyses (XRF 456, 457 and 463) detected copper

with minor lead. One piece of Egyptian blue. Evidence of Egyptian blue manufacture?

National Significance – Yes if Egyptian blue manufacture

Regional Significance - Yes if Egyptian blue manufacture


Research Potential - Yes if Egyptian blue manufacture


4.6.10 Waterbeer Street (1888)

Evidence – described as a crucible, but probably a drug jar (T. Cadbury), analyses (XRF 450)

detected lead and minor traces of zinc and arsenic.

National Significance - ?

Regional Significance - ?




Research Potential - ?



4.7.1 Acorn Street (1988) Evidence – scatter of smithing slag in Roman, medieval and later medieval levels. One piece of

copper alloy stained slag in the medieval phase.





Retention Advice – asses in light of review of smithing across the city.

4.7.2 Albany Road (1978-84)

Evidence – smithing debris, currently un-phased, possibly Roman and medieval. Large assemblage

of copper alloy casting debris in medieval layers.


Regional Significance – Yes (copper alloy casting)

Community/Group Significance – Yes – as examples of debris type.

Research Potential - Yes –part of an overview of medieval non-ferrous metalworking in Exeter

Retention Advice - asses in light of review of smithing across the city.

4.7.3 Bartholomew Street East (1980)

Evidence – c. 5kg of smithing debris, multi-period site but material is currently un-phased. An object

described as a tuyere was probably daub (XRF 458 and 459).


Regional Significance – yes if phased and distribution of smithing activity within the Roman or

medieval settlements is researched




Research Potential - yes, see regional Significance


4.7.4 Bartholomew Street West (1974)

Evidence – c 6kg of smithing debris, multi-period site but material is currently un-phased, plus sprue.


Regional Significance - yes if phased and distribution of smithing activity within the Roman or

medieval settlements is researched


Research Potential - yes, see Regional Significance


4.7.5 Bowhill House (1977) Evidence – a little smithing slag, plus possible glass cullet (XRF 497, high manganese).






4.7.6 Cathedral Close (1971-6 & 1994)

Evidence – c. 14kg of smithing debris, medieval bell casting.

National Significance – Yes for bell casting

Regional Significance - Yes for bell casting, and yes for smithing to research distribution of smithing

activity in Roman and/or medieval Exeter.


Research Potential – Yes

Retention Advice -



4.7.7 Cricklepit Mill (1989-90)

Evidence – one fragment of post-medieval smithing slag.





Retention Advice - Discard .

4.7.8 Cricklepit Street (1974 & 1985)

Evidence – fragments of smithing slag and corroded iron objects.





Retention Advice -

4.7.9 Exe Bridge (1975-76)

Evidence – smithing slag and copper alloy working. Copper alloy strip (L462, XRF 482) was arsenical

copper with a trace of tin. Another (strip L461 XRF 483) was leaded gunmetal. A piece of glazed

lining detected copper, tin and antimony (XRF 496).


Regional Significance – Yes, distribution of smithing and copper alloy casting across the city


Research Potential - Yes, copper alloy casting across the city

Retention Advice - Reconsider after review of smithing and cu alloy working across the city after

mould assessment .



4.7.10 Exe Street (1985-86)

Evidence – Over 20kg of smithing debris, some copper alloy stained slag.




Research Potential - Yes, distribution of smithing activity across the city.


mould assessment.

4.7.11 Exeter Excavations (1970-81)

Evidence – Roman crucibles returned from J Bailey 2003


Regional Significance – Ye, evidence of copper alloy production across Exeter


Research Potential - Yes, alloy type, use of Antimony.


4.7.12 Flowerpot (1987)

Evidence – c. 3kg of smithing slag





Retention Advice - Re-asses after review of smithing activity across city.

4.7.13 Friernhay Street (1981)



Evidence – several kg of smithing debris, possibly Roman military, some evidence of copper alloy

working reported on by Bayley (1989b). A tuyere fragment was analysed (XRF 480) and detected

copper, zinc, silver and lead.


Regional Significance – Yes, if Roman military


Research Potential - Yes, if Roman military


mould assessment.

4.7.14 Goldsmith Street (1971-72)

Evidence – c 20kg of smithing debris, evidence of copper alloy working, including possible parting

vessel (XRF 489), and detected copper, zinc and silver. One crucible sherd (XRF 488) detected

copper and silver, another (crucible 49-36-4) and analyses (XRF 500-502), detected major zinc, with

minor copper, silver, tin, antimony, and lead. Unclear about phasing, but close to Fort fabrica.

National Significance – Yes , crucibles Saxo-Norman

Regional Significance - Yes if material can be stratified


Research Potential - Yes if material can be stratified


mould assessment.

4.7.15 Haven Banks (1988)

Evidence – 0.5kg of smithing debris








4.7.16 High Street Wheatons (1927), (1975-6) 197 High Street ( ? ), and 41-2 High Street (1980) High Street, Woolworths (1933)

Evidence – small quantity of smithing slag and a few crucible sherds. The pilgrim mould in the gallery

(Gallery LM66) was recovered from the Woolworths site and was analysed (XRF447) and zinc, gold,

mercury and lead were detected. A crucible was recovered from Wheatons (XRF 451) and only

minor zinc was detected. At 197 High Street a crucible sherd was recovered and analysis (XRF 486

and 487) detected zinc and silver with minor levels of copper and lead.






mould assessment .

4.7.17 Holloway Street (1974)

Evidence – Smithing slag (un-weighed, 42 small bags). Un-phased.






4.7.18 Katharine’s Priory (1976-79)

Evidence – small amount of smithing slag.








4.7.19 King Street 5-6 ( ? )

Evidence – small amount of smithing slag (fragments).






4.7.20 Lower Coombe Street (1989-90)

Evidence – c. 1kg of Roman smithing slag






4.7.21 Magdalene Street (1976 and 1986-88)

Evidence – 0.5kg of medieval smithing slag, c 8kg of post-medieval smithing slag (residual?), plus

some copper alloy stained slag.






mould assessment.



4.7.22 Mermaid Yard (1977) Evidence – c. 10kg of copper alloy stained slag indicating copper alloy working, medieval bell

founding.





Retention Advice - Reconsider after review of cu alloy working across the city after mould

assessment.

4.7.23 Nelson Close (Topsham Fort) (Roman fort) (? )

Evidence – a few fragments of smithing slag.





Retention Advice – 100% evidence of smithing in Fort.

4.7.24 North Gate ( ? ) Evidence – small quantity of smithing slag.






4.7.25 North Street (1971) Evidence – c. 3kg of smithing slag and iron artefact fragments.








4.7.26 Paul Street (1982-85)

Evidence – Roman – smithing slag; medieval c.7kg smithing debris; post-medieval c. 2kg of

smithing slag (residual?). Extensive evidence for medieval casting, including bells. Material includes

hearth structure, spills of alloy (one large one, was leaded gunmetal (XRF 481), copper alloy stained

slag and mould fragments.


Regional Significance - yes




mould assessment.

4.7.27 Preston Street (1976-77)

Evidence – c. 2kg of iron smithing slag and 2kg of copper alloy stained slag indicating copper alloy

casting, plus c 0.5kh of heath lining some stained with copper alloy. Un-phased.


Regional Significance – Yes for distribution of copper alloy working in the city




mould assessment.

4.7.28 Quay (1985-86)

Evidence – corroded iron objects







Retention Advice – either store iron objects in suitable conditions or discard.

4.7.29 Queen Street (1978-79)

Evidence – c. 0.4kg of smithing debris






4.7.30 Rack Street (1974-78)

Evidence – c 10kg of smithing debris, including 3 possible bloom fragments (Box EX3168), which

must be extracted and conserved.


Regional Significance –Yes, if phasing is available


Research Potential - Yes, check ironwork catalogue

Retention Advice - Re-asses after review of smithing activity across city, possible bloom fragments

should be analysed if phased.

4.7.31 Shooting Marsh Stile (1984)

Evidence – 12kg of smithing debris and a small amount of copper alloy stained slag, no report, un-

phased.


Regional Significance – Yes, copper alloy working in Exeter




Research Potential - Yes, copper alloy working in Exeter


mould assessment.

4.7.32 Southernhay Gardens (1974) Evidence – non-diagnostic “blown” fired clay





Retention Advice – retain for reference collection.

4.7.33 Trichay Street (1972-74) Evidence – site of the Roman fort fabrica, significant smithing evidence, including smithing slag and

hearth bottoms. Iron artefact assemblage must be examined for rods, bars, examination of the x-

radiographs showed presence of hammerscale and copper alloy droplets. Evidence of copper alloy

working. Some material reported by Wilthew (1986) and Bayley (1989a). A copper spill (SFN 469)

was shown to be leaded tin bronze (XRF 477), and another (SFN 471) was pure copper (XRF 478).

A copper alloy sheet (SFN 466) was gunmetal (Cu/Zn/Sn, XRF 479). A mould was analysed (XRF

484 and 485) detected copper and silver.

National Significance - yes





4.7.34 Valiant Soldier (1973-1974)

Evidence – c. 3kg of smithing debris, plus lots of iron artefacts, un-phased.


Regional Significance - yes






4.7.35 Waterbeer Street (1975)

Evidence – c 1kg of smithing debris







4.8.1 Bonhay Road (2000)

Evidence – one thin hearth bottom






4.8.2 Cowick Street (1999-2000)

Evidence – large assemblage of cauldron mould fragments from late medieval contexts. Only a few

boxes examined and a selected number of pieces were analysed (XRF 506-7, 510-514) and showed

varying results but copper, zinc, tin arsenic and lead were detected.. Not fully assessed, see proposal

on mould retention. Also the manila mould on show in the gallery (Gallery S&G154) was analysed

(XRF 503 and 504) and showed the presence of copper and lead with minor arsenic. , as well as a

manila (122 1993.8) (XRF505), the manila was not from Exeter but an unknown location and was

copper, tin with significant lead and minor arsenic.







Retention Advice - reviewed after overall Exeter mould assessment.

4.8.3 Exeter Road Topsham ( ? )

Evidence – modern clinker






4.8.4 Fishers Square ( ? )

Evidence – 2 fragments of smithing slag






4.8.5 Market Street and Smythen Street (1995-99)

Evidence – c. 3kg of smithing debris








4.8.6 Northcott Warehouse ( ? )

Evidence – c. 3kg of smithing slag


Regional Significance – Yes if phased




5 Discussion

The Royal Albert Memorial Museum metallurgical collection contains a wide range of material of

national and regional significance. Material from 115 sites contained in c. 223 boxes was examined.

The material presents an excellent record of the history of metal production and metalworking in the

British Isles, but with some notable and important omissions, discussed below. The results are

summarised in Table 3. The evidence from the main periods is discussed, with the dating

information available.

Period Non-

ferrous

Smelting

Non-

ferrous

Working

Iron

Smelting

Iron

Smithing

Bronze Age Yes

Iron Age Yes Yes

Roman Yes Yes Yes

early Medieval

Medieval Yes Yes Yes

Post-Medieval Yes Yes



Table 3 Summary of evidence of metalworking in Devon by period

Bronze Age metalworking is evidenced from 5 or 6 sites predominantly by metal finds that display the

range of compositions expected, i.e. copper, copper arsenic and copper tin alloys, e.g. Dainton, Ash

Farm and Gitisham Barrow etc.. All sites are of national importance. Iron Age iron smelting was

present on five sites, two of which (Dean Moor and Kes Tor) did not produce evidence of smithing

which is significant. Three sites produced evidence of both iron smelting and iron smithing, and one

(Beer Head, date uncertain) produced only smithing. This is also significant in that it would be

expected that the majority of Iron Age occupation sites, certainly from the later Iron Age (400/200BC

onwards) would be expected to produce smithing evidence. The lack of recovery of hammerscale is

important in this respect (see recommendations). All the smelting sites are of national importance

and the smithing sites are of regional importance. It is important when considering iron smithing

debris is a vital indicator of iron consumption not only in the Iron Age but in all periods. It is of

particular significance in Iron Age studies as the survival and recovery of iron artefacts from Iron Age

sites is poor.

Outside of the Blackdown hills there is little evidence for Roman iron smelting, one fragment was

recovered from Goldsmiths Street in Exeter and a small assemblage from Bolham Roman Fort

(Tiverton) but has the morphology of Iron Age smelting slag. Fifteen Roman sites produced evidence

of iron smithing most significant at Pomeroy Wood (A30 Scheme), Trichay Street and at Pauls Street

in Exeter. Although no hammerscale was recovered from the excavations (see recommendations)

there was evidence for hammerscale entrapped in the corrosion products of some iron objects visible

on the contemporary x-radiographs. Holcombe Villa produced only a small quantity of smithing

debris, but excellent examples of smith’s tools were found. Further research should be undertaken on

the distribution of iron smithing across the Roman settlement in Exeter, and further work could be

undertaken on the Pomeroy Wood, Trichay Street and Paul Street assemblages, which if confirmed

smithies had been excavated these sites would be of national importance. Thirteen sites generated

evidence of non-ferrous metalworking, of which ten were within Exeter. All the non-ferrous working

evidence requires research to synthesise the evidence, to identify the major sites and consider the

range of alloys in use.

The early medieval period (5th-10thC AD) is poorly represented in the archive, no site was identified to

this period alone, but within the stratigraphic sequence of Exeter early medieval levels will exist.

The evidence of medieval iron smelting sites is sparse primarily due to the lack of secure dating, e.g.

sites such as Hemyock, or that the quantity of slag is small and may be redeposited. This is a critical

period of innovation in iron smelting technology with the move from human powered bellows to water-

powered bellows. Thus in the case of the Blackdown hills the 14th/15th century sites will be adjacent

to streams or small rivers. Eighteen sites produced evidence of blacksmithing, again nearly all



medieval occupation sites produce some evidence of blacksmithing and so the list will be longer if

other sites re dated. The evidence from the Cistercian House of Buckfast Abbey is of national

importance and requires further research. The evidence across Exeter should be reviewed to assess

whether there is any evidence for craft specialisation in specific areas of the city. The evidence of

non-ferrous metalworking in Exeter is of national importance. Sites have produced significant

evidence of bell casting and other copper alloy working. There is intriguing evidence for the use of

copper-tin-antimony alloys that have been observed elsewhere, and probably have a

Cornish/Southwest source, but their composition has implications for ore resource exploitation and

smelting technology.

The slag recovered from the 18th century site at Tiverton was identified as smelting slag but may be a

slag derived from the refining of cast iron. The site deserves further archaeological and historical

research. Thirteen sites with post-medieval iron smithing evidence were noted, but the material

needs to be assessed as to whether the deposits are residual from either roman or medieval activity.

The evidence in Exeter for post-medieval copper alloy working in particular the Cowick Street Site is

of national significance.

Very few assemblages have been highlighted as having importance for Community/Group

Significance. Those with research potential could be steered towards relevant groups, in particular

groups wishing to undertake survey work in their local parish or area.

6 Recommendations

A number of key recommendations are made to refine the assessment, improve archive quality,

identify research potential, provide opportunities for improved public interaction with the collection and

contribute to the public understanding of science. Some of these suggestions could be more easily

achieved via the web rather than other means, but with some nudge towards the web at suitable

instances, e.g. gallery guides (written or verbal).

6.1 Improve archive quality

6.1.1 Firm up dating on as many sites as possible. Improved dating of deposits will identify those that are predominantly residual, hence are unstratified

and could be significantly reduced in volume. Material securely dated to a specific period may/will

change its significance.

6.1.2 Museum to seek examples of specific processes

The museum lacks examples of some processes in particular the smelting of copper tin and lead.

Opportunities should be sought to obtain suitable examples e.g. of tin slag for the gallery and to

develop a reference collection.



6.1.3 Ensure optimum quality for future accessions to the museum It was very significant that the most important indicator of iron smithing was absent from the

collection. To properly assess the future deposition of smithing debris it is essential to know whether

hammerscale was present on the site. Hence it is recommended that the Museum suggest to the

County Archaeologist that they insist all archaeological contractors show their methodology for

recovering hammerscale, both on site, during excavation and at the post-excavation stage (following

national guidelines established by English Heritage (Centre of Archaeology Guidelines for

Archaeometallurgy, p6).

6.1.4 The non-ferrous casting assemblages

To develop a methodology to archive the current major of mould material and the expected arrival of

further substantial collections (see separate paper: Proposal for the Curation of the Cauldron Mould

Assemblages).

6.2 Identify Research Potential

Identify research themes within the archive through links with universities for research at the

undergraduate, masters and doctorate levels. Some suggestions are:

Review change in copper alloy composition usage across Exeter from the Roman period to

the Post-medieval period

Review evidence of iron smithing across Exeter.

Explore iron smelting sites in Devon other than the Blackdown Hills.

Re-assess specific sites in particular assess all artefacts (e.g. iron slag and iron artefacts)

and ecofacts, e.g. Trichay Street, Paul street and Pomeroy Wood.

6.3 Public interaction and the public understanding of science. The archive offers excellent opportunities for Museum Volunteers to improve the archive by e.g.

sorting through bags of smithing debris and re-bagging spate artefacts types, e.g. hearth bottoms,

smithing slag lumps, hearth lining etc. Educational collections of metalworking debris could be

established. Highlight the importance of Devon’s metallurgical heritage, for example there was little

evidence of the importance of the Dartmoor tin industry. Metals and metalworking residues offer

exceptional opportunities to improve the public understanding of science, and directly interact with

school curricula. This can range from simple questions as to what is a metal, what is an alloy,

through to the use of x-rays, and their interaction with matter.



7 Conclusions

The metalworking archive of the Royal Albert Memorial Museum contains material of national and

regional importance. It provides evidence for many metalworking activities of Devon’s industrial

heritage. There are opportunities to refine the archive and ensure it makes a more significant

contribution to the Museums presence, including web presence.

Gerry Mcdonnell Archaeometals

22 January 2012

References

Bayley J. 1989a Some evidence for non-ferrous metalworking from Roman Exeter, Devon. .

Ancient Monuments Laboratory Report (New Series) 54/1989 English Heritage

Bayley J. 1989b Evidence for non-ferrous metalworking from Frien Hay Exeter, Devon. . Ancient

Monuments Laboratory Report (New Series) 55/1989 English Heritage

Bayley, J., Crossley D. and Ponting M. 2008 Metals and metalworking. A research agenda for

archaeometallurgy. Historical Metallurgy Occasional Publication Number 6. Historical Metallurgy

Society Ltd. London

Blaylock S.R. 2000 Excavation of an early Post-medieval Bronze Foundry at Cowick Street, Exeter

1999-2000 Devon Archaeological Society Proceedings Vol 58 1-92

Fitzpatrick A.p., , Butterworth C. A. and Grove J 1999 Prehistoric and Roman Sites in East Devon:

the A30 Honiton to Exeter improvement DBFO, 1996-9. Wessex Archaeology Report Number 16.

Gent, T H; Quinnell, H. 2000 Excavation of a causewayed enclosure and hillfort on Raddon Hill,

Stockleigh Pomeroy. Devon Archaeological Society Proceedings Vol 57 1-75

Maxfield, V. A. 1991 Tiverton Roman Fort (Bolham): excavations 1981–1986. Devon Archaeological

Society Proceedings Vol 49 25-98



Needham S., Silvester R. J. and Howard H. 1980 An assemblage of Late Bronze Age

metalworking debris from Dainton, Devon. Proceedings of the Prehistoric Society. Vol 46 177-215

Todd M. 2007 Roman military occupation at Hembury (Devon). Britannia Vol 38 107-123

Wilthew P. 1986 Examination of slag from various Roman sites in Exeter. Ancient Monuments

Laboratory Report (New Series) 44/1986 English Heritage



Appendix 1

List of Spreadsheets

1 exeter_museum_metalworking_master97ver.xls

The raw data recorded at the museum and processed. The headings are self-explanatory,

the explanation of short-hand classifications are given below.

2 exeter_museum_by_period_97ver.xls

A summary of the sites with period data where known. Hence can be sorted by period. The

type of evidence is very superficial, presence of evidence e.g. iron smithing.

3 exeter_museum_boxees_97ver

A summary of the boxes examined. Requires some editing to ensure the boxes can be

ordered in numerical order

4 filtered_xrf_data_97ver

Raw XRF data, blank columns removed

5 filtered_xrf_data_processed_97ver

Processed data.

Shorthand terminology used in the master spreadsheet

Diagnostic Ferrous Slags and Residues

Ore - Iron ore

Tap - Tap Slag

IA Slag - Smelting Slag

SSL - Smithing

HB - Hearth Bottom

Fe obj - Metal



HS - Hammer Scale

Cin - Cinder (diagnostic – rare)

Diagnostic Non-Ferrous Slags and Residues

Cruc - Crucible

Mould - Mould

Cu stained SSL or Cu stained slag - Slags with non-ferrous corrosion

Metal Spills – frozen spills of molten metal.

Non-Diagnostic Slags and Residues

HL - Hearth or Furnace Lining

Cin - Cinder



Appendix 2

Pomeroy Wood – Xrays RAMM Archive box 91, paper archive file 102

3/2004

Plate number Object number Comment

7929 2164 Hammerscale (HS)

2192 HS

2176 HS

No number HS

7930 2357 ?HS

7932 2124 HS or Cu

2186 HS

2165 HS

7933 2116 HS

7934 2285 HS

2286 HS

7935 2305 HS

2277 Plus Cu

7936 2306 HS (long object)

2289 HS

2328 HS

7937 2322 HS (left hand object)

2289 HS (dense nail)



2304 HS (horizontal nail)

Also 2 others HS

7938 2242 HS

2204 HS

2243 ?Cu

7939 3 artefacts with Cu

7940 2282 HS

2217 HS

2219 HS

2283 HS

7941 2208 Slag, but could be bloom

7943 2040 HS

7946 2111 ?just a scratch on x-ray

plate

7952 3012 HS (thin rod)

970 HS

7953 2253 HS (left hand frag)

3066 HS

7954 4207 Slag

3621 ?Cu

8060 1371 HS (long item)

1766 HS

1745 HS (bottom row, 2nd from

left)

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