Wednesday, September 14, 2011

Irish Copper Age houses in a radiocarbon landscape: a reply to Dr Charles Mount

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Last week archaeologist Dr Charles Mount published a blog post about the relatively rare phenomenon of houses in the Irish Copper Age. As is the way of such things, it was rapidly seized upon by a number of archaeologists and related groups on Facebook and quickly ‘shared’ and ‘re-shared’. On my own Facebook page I shared it with the comment that it was a ‘brief, but elegant, summary of Copper Age houses’.  While I don’t know Dr Mount personally we are ‘Facebook Friends’ and he added a comment asking that if I knew of any more sites he had missed, to let him know. The simple answer was: No, I haven’t a notion about any other houses dating form that period. Rather than leave it there, I started thinking and doing a little research … and I still have no extra houses to add to the list. But that’s not quite the end of the story.

But first some background (it would be best to go back and read the original blog post now) … Mount dates the Irish Copper Age (or Chalcolithic) to the period 2600-2400 cal BC to 2200/2100 cal BC. This is a period bounded by the end of the Late Neolithic and it’s Grooved Ware pottery on one side and the earliest portion of the Early Bronze Age on the other, and sees the introduction of the Beaker Pottery form. In terms that I am more comfortable with, it dates roughly from 4100 radiocarbon years BP to 3750 radiocarbon years BP.

Mount notes that only about a dozen houses can be properly said to date to the Copper Age, and that these are confined to a mere four sites.  These are: Lough Gur, Co. Limerick; Monknewton, Co. Meath; Graigueshoneen, Co. Waterford; and Ross Island, Co. Kerry. Obviously, the Lough Gur sites were investigated in the years before the development of radiometric dating, but the others are all supported by good dates and finds of beaker pottery. Mount concludes that the light construction of many of the known examples may explain why so few houses have been identified. He also comments that a series of stake-built oval structures ‘would leave a meaningless jumble of stake and post-holes associated with spreads of settlement material.’ In a comment on the original blog post, John Tierney of Eachtra Archaeological Projects, noted that ‘hard-to-spot clay walls’ may have been more common in the past than we had previously believed. Such a situation would leave us inferring the former presence of structures by identifying spaces ‘devoid of features in a ground plan.’

With these problems in mind, I approached my Catalogue of Radiocarbon Determinations and Dendrochronological Dates with the intention to seeing if this highly-specialised way of apprehending the archaeological world could bear fruit. With some simple data filtering, my current catalogue of 5351 radiocarbon determination was quickly whittled down to 294 from the island of Ireland. For this process, my frame of reference was an examination of the ‘raw’ radiocarbon dates in the range from 4100 to 3750 radiocarbon years BP.

Some of the evidence we can dismiss immediately as not pertinent to the question of housing in the Copper Age. Into this category can go 80 dates from various burnt mounds and burnt spreads and 12 trackways of different forms.  Sixty-four dates can be excluded as they are directly or indirectly associated with burials such as wedge tombs and cists – a number of these are now, thanks to the work of Anna Brindley in refining the chronology for Bronze Age pottery styles, considered to be anomalous. A further nine dates are associated with Late Neolithic Grooved Ware pottery. Fourteen relate to environmental samples, largely associated with dates on pine stumps from the Céide Fields complex. Two dates relate to log boats (Carrowneden, Co. Mayo & Lurgan, Co. Galway); one is associated with a wooden polypod bowl (Tirkernaghan, Co. Tyrone); one is from peat associated with a necklace (Milmorane, Co. Cork). One date is from the henge at Tonafortes, Co. Sligo, and eight are from the Newgrange pit circle/henge. One relates to an unpublished Late Neolithic timber circle at Liscolman, Co. Antrim. Twenty four dates are broadly associated with megalithic tombs, especially passage tombs, though a number do relate to court tombs. Some of the older dates relate to pre-tomb habitation (e.g. at The Mound of the Hostages, Tara and Ballyglass, Co. Mayo) and may be treated with some degree of caution.

When all of the above are removed, along with a few anomalous dates, a few duplications in the catalogue, and the data relating to sites already identified by Mount, we are left with 61 radiocarbon dates. Let me be clear – I’m not arguing that every one of these dates represents a Copper Age settlement … I just think that it may make a good preliminary list from which future research and debate may just blossom. The nature of such a blog post as this means that I have not had the opportunity to go and revisit every publication cited here to check if there could be a Copper Age house there – I think I will leave that to others!

The first cluster of dates 13 dates relate to sites that have already produced beaker pottery and should, perhaps, be looked at again to gauge whether or not there is sufficient evidence to suggest the presence of a house or similar structure. At Waterunder, Mell, Co. Louth, an occupation layer that contained beaker pottery and end-scrapers returned a date of 3960±33BP, (2572-2346 cal BC, Wk-17457) (McQuade 2005, 35). At Milltown North, Co. Limerick, a ‘scoop’ that contained beaker pottery returned a date of 3895±34BP (2473-2236 cal BC, UB-6065) (Grogan 2007, 302). Oak charcoal from a pit associated with beaker pottery at Broomfield, Co. Dublin, dated to 3880±30BP (2467-2235 cal BC, GrN-13879) (O'Brien 1988, 120). Charcoal from a pit that contained beaker pottery, flint débitage and charred seeds at an Early Christian enclosure at Curaheen, Co. Cork, produced a date of 3920±70BP (2579-2155 cal BC, Beta-171422) (Kerr et al. 2010, 153). However, the biggest single concentration of dates comes from Ballynagilly, Co. Tyrone. The site is better known for producing a Neolithic house – one of the earliest excavated – but there was also substantial evidence for beaker-related activity there too. The nine dates ranged from 4055±50BP (2859-2471 cal BC, UB-553) – from charcoal from dark layer – to 3780±70 BP (2459-2030 cal BC, UB-557) – again from charcoal associated with Beaker pottery (Smith et al. 1973, 219; 1971, 106-7).

At Eglinton (Gortenny Td.), Co. Londonderry, there are three dates that are of interest in the current context. Charcoal from the basal fill of a possible hearth dated to 3830±50BP (2463-2142 cal BC, Beta-230118); a large pit returned a date of 3770±50BP (2398-2031 cal BC, Beta-230119); and the fill of a stakehole came back at 3950±40BP (2571-2307 cal BC, Beta-230120) (Chapple 2008, 172).

Seven dates are related to known Bronze Age settlements. At Ballybrowney 1, Co. Cork, charcoal from the fill of a slot trench associated with Structure C dated to 3910±70BP (2575-2154 cal BC, Beta-201046) (O'Sullivan & Stanley 2005, 149). Charcoal from a posthole associated with the enclosure at Site 35D, Laughanstown, Co. Dublin, returned a date of 3847±35BP (2459-2205 cal BC, OxA-12811) (O'Sullivan & Stanley 2005, 149). Charcoal from occupation soil overlying pit at Meadowlands, Downpatrick, Co. Down, dated to 3795±75BP (2463-2034 cal BC, UB-472) (Smith et al. 1973, 213). Fruitwood and ash charcoal from the lower fill of a pit associated with the roundhouse at Cloghnabreedy, site 125.3, Co. Tipperary, dated to 3762±35BP (2289-2041 cal BC, UB-7377) (Stanley et al. 2009, 170; McQuade et al. 2009, 368). At the enclosed settlement at Chancellorsland, Site A, Co. Tipperary, a date of 4085±60BP (2872-2486 cal BC, AA-10297) was achieved on charcoal from the basal layer a recut of the outer ditch (Warner 2008a, 665). Charcoal from a grey layer under the ramparts at Rathgall, Co. Wicklow, provided a date of 3780±140BP (2580-1776 cal BC, UB-2344) (Anon. 1987-1988, 79). A date of 4021±48BP (2851-2458 cal BC, UB-3969) came from charcoal (Area A) at the hilltop enclosure of Knockacarrigeen Hill, Tuam, Co. Galway (Carey 2002, 61-62). Charcoal from a midden at Illauntannig, Co. Kerry, dated to 4030±60BP (2863-2350 cal BC, UCLA-2773AA) (Berger 1992, 884, 885). Although, not strictly evidence of habitation, this date may be taken to suggest that a contemporary house (or houses) lay somewhere in the vicinity.

There is a group of 11 dates that are only associated with single pits. At Robswalls (Paddy's Hill), Co. Dublin, sea shells from a pit produced a date of 4040±70BP (2872-2351 cal BC, GrN-12337) (Manning & Hurl 1989-1990, 74). The pit was associated with a flint scatter and also contained animal bones, hammerstones, a polished porcellanite axe head, and several hundred lithics. At Granny Site 27, Co. Kilkenny, charcoal from isolated pit dated to 3982±36BP (2580-2350 cal BC, UB-6314) (O'Sullivan & Stanley 2005, 148). Two dates came from the NAC excavations on the A1 (Loughbrickland) Dualing Scheme, Co. Down [there’s also a coffee table book, free to download from Roads Service, and a colour poster by NAC]. The first of these was from a pit in Area 8 (Aughintober td) and the second came from the fill of a pit associated with what is interpreted as Phase 2 of a short-term camp site (Area 2). The former date was 3890±60BP (2564-2154 cal BC, Beta-217343), while the date from the camp site returned as 4030±80BP (2872-2345 cal BC, Beta-217346) (Chapple et al. 2009, 7, 136; Chapple 2008, 164, 165). At the predominantly Late Mesolithic site at Toome (Brecart Td.), Co. Antrim, a pit (Area N) dated to 3880±40BP (2470-2209 cal BC, Beta-219472) (Chapple 2008, 160). At Ballycorick, Co. Clare, a pit returned a date of 3870±40BP (2467-2208 cal BC, Beta-179172) (Grogan 2007, 99, 170). Charcoal from a pit with slag at the industrial site at Kinnegad 2, Co. Westmeath, produced a date of 3910±40BP (2549-2216 cal BC, Beta-177425) (Carlin et al. 2008, 136). Charcoal from a pit fill in Area I at Gortore 1, Co. Cork, dated to 3832±36BP (2458-2151 cal BC, UB-6768) (O'Donoghue 2010, 10). Charcoal from three separate pits at Faughart Lower 6, Co. Louth, produced dates of 4030±50BP (2855-2463 cal BC, Beta-217946), 4070±50BP (2863-2474 cal BC, Beta-217947), and 4010±40BP (2832-2461 cal BC, Beta-217948) (Hayes 2007, 68, 72).

The final group, and unfortunately the largest, is a set of 25 dates where I have only tantalizingly brief details of the site. For example, at Demesne, Co. Westmeath, a date of 3914±55BP (2567-2208 cal BC, no laboratory code cited) was returned from a ‘settlement cluster’ (source: INSTAR People of Prehistoric Ireland Database). The catalogue contains a substantial list of dates provided by CRDS in MSExcel form. Overall, they list good, clear context information (and I remain indebted to the company for providing the information), but the original final reports would be necessary to fully evaluate the significance of the information they provide. It is wholly possible that these dates are the keys to identifying further Copper Age houses and settlements, but further research is required to track down and analyse this body of information. At Kilshane Site 5, Co. Dublin, charcoal from an artefact-rich deposit in the enclosure ditch (possibly of a causewayed enclosure) returned a date of 3784±69BP (2459-2033 cal BC, Wk-18167). Killescragh (E2070), Co. Galway, is described as having contained ‘wooden structures and a burnt mound’. Charcoal from a hearth there produced a date of 3855±107BP (2618-1979 cal BC, Wk-21246). Treanbaun (E2123), Co. Galway, is listed as an ‘Early Medieval burial site and Bronze Age remains’. Here, a date of 3883±75BP (2568-2141 cal BC, Wk-22715) was returned from charcoal in the fill of a possible mine. Charcoal from in situ burnt timbers at the site of ‘industrial early historic activity’ at Gortnahoon, Co. Galway, produced a date of 3953±63BP (2826-2210 cal BC, Wk-21333).

The final 20 dates in this group are drawn from the NRA Database. Again, they are severely lacking in all the contextual information I would like, but they still interesting pointers for future research. At Grace Dieu West, Co. Waterford, charcoal from pit at a ‘Neolithic and Bronze Age settlement’ dated to 3860±40BP (2464-2206 cal BC, Beta-170160). A date of 3850±70BP (2546-2057 cal BC, Beta-171410) was returned from charcoal from a pit at Barnagore 2, Co. Cork, at a site described as ‘pit, Stakeholes.’ Charcoal from pits at Adamstown 1 and 2 Co. Waterford, provided dates of 4090±90BP (2896-2460 cal BC, Beta-2097590) and 3840±40BP (2462-2154 cal BC, Beta-209755), respectively. Adamstown 1 is described in the database as ‘Kiln, Pits, Metalworking site, Kiln - corn-drying , Stakeholes’, while Adamstown 2 is simply given as ‘Settlement, Industrial - Multi-period’. Charcoal from another pit, this time at a site of ‘Pits, Stakeholes, Postholes’ at Curraheen 1, Co. Cork, provided a date of 3940±70BP (2620-2205 cal BC, Beta-171422). At Curraheen 5, Co. Cork, alder charcoal from a pit dated to 3850±40BP (2461-2205 cal BC, Beta-181754). The site is described as a ‘Burnt mound, Pit, Burial mound.’ Other sites in Co. Cork include an apparently isolated pit at Carrigrohane 4 that dated to 3990±60BP (2836-2297 cal BC, Beta-178202); A ‘Bronze Age burnt mound, Hoard, Cremation pit, Flint scatter’ at Fermoy 2 dated to 3810±40BP (2457-2137 cal BC, Beta-201032); One of a number of ‘Bronze Age pits’ at Lisnasallagh 2 returned a date of 3890±60BP (2564-2154 cal BC, Beta-201097); while at Barnagore 4, a ‘Bronze Age pit, spread’ dated to 3760±40BP (2292-2036 cal BC, Beta-171415). In all of these cases, except Barnagore 4, the date was on charcoal from a pit; in this case, the date was returned from a charred seed.

There are three dates from Co. Meath that fall into our time frame – two from pits and one from a posthole. At Dunboyne 4, a site described as ‘Bronze Age Kiln, Pits, Postholes,’ a date was returned of 3860±40BP (2464-2206 cal BC, Beta-231934 from one of the postholes. A site of ‘Bronze Age Cremation pits, Hearth’ at Knockmark 1 dated to 3780±40BP (2342-2041 cal BC, Beta-231945), while one of the ‘Bronze Age pits & postholes’ at Raynestown 2 produced a date of 3780±40BP (2342-2041 cal BC, Beta-241285). At Tullahedy Site TUVW, Co. Tipperary, charcoal from a pit under a burnt mound spread produced a date of 3940±66BP (2618-2206 cal BC, UCD-116). While this particular date could have been removed from the data-set at an earlier point, the fact that the site is listed in the NRA Database as ‘Bronze Age enclosure & burnt mound’ intrigues me to the point that (without seeing a final publication on the excavation) I suggest it may warrant further and closer study.

Two dates come from excavations in Co. Kilkenny. At a collection of ‘Bronze Age pits’ at Garrincreen, ‘charred remains from pit with pottery’ returned a date of 3780±40BP (2342-2041 cal BC, Beta-205170), while charcoal from a stakehole at Granny 28 dated to 3913BP (UB-6637). Unfortunately the NRA database lists the standard deviation for this date as ±0, limiting its full potential for contributing to our knowledge. Charcoal from two pits, both in Co. Kildare, one at Loughlion Site 8 and the other at The Curragh Site 10 produced dates of interest in the current context. The first site is described as ‘Bronze Age Pits, Postholes, burnt mound’ and dated to 3838±74BP (2480-2041 cal BC, Wk-12814), while the second produced a date of 3780±30BP (2295-2059 cal BC, GrN-30089) and is listed as ‘Bronze Age pits & postholes.’ The final date in this preliminary collection is from Newtownbalregan 2, Co. Louth, which is described as ‘Hut site, House – Neolithic.’ Although the site produced a date of 3990±46BP (2829-2346 cal BC, Wk-19929), neither the material it was derived from, nor any contextual information is listed.

Where does all this data leave us and what conclusions can we draw? Firstly, I think we now have a decent preliminary list of places we should start looking for Copper Age houses. It is my contention that the explosion of archaeological excavations – and the resulting tsunami of radiocarbon dates – means that few, if any, archaeologists will ever gain mastery of all that data and knowledge. In such a situation no one person will be able to read and investigate all the available literature to sift out the sites relevant to their personal research. Obviously I’m biased, but I believe that starting with a catalogue of known radiocarbon dates is one strand in mining this mountain of data. I would argue that no amount of other forms of research could have independently produced this list. That is not to say that there are sites I have missed out that other researchers, using other means, could have found – that is why this must be but one strand among many.

Have I given Dr. Mount even one more positive identification of a Copper Age house? – No, definitely not.  In my defence, I believe that we now have a list of about 60 excavations where we can start looking for these sites. If even one or two could be shown to be houses of the right period, then, I think, we will have achieved a great deal. However, there is a broader question that this list may help to draw us towards – the wider nature of activity during this period. As I’ve said above – I’ve not had the leisure to read all the pertinent details of even the excavations reports immediately available to me. It is for this reason I’m pretty sure that many of the sites I’ve listed will, ultimately, not produce any new evidence for houses that we have missed. However, I could not help noticing a trend as I wrote up this data – there do seem to be an awful lot of (apparently) isolated pits that have produced Copper Age dates. Another trend - and one noticed by Mount in his blog – is the lack of actual copper. Not one of the features that I have listed here has produced a single scrap of copper. In the context of the known houses, Mount suggests (in the comments to one of the Facebook ‘shares’) that copper may have been regarded as somehow ‘taboo’ and banned from domestic spaces. That argument has a definite appeal, but taken in the broader context of all of these other excavations, radiocarbon dates and features, it hints at some different mechanism at work. Maybe copper was so highly regarded and valued that it was not deliberately placed in the ground. Maybe there are issues regarding its final disposal that elude archaeological recovery. I have no answer to any of these questions – only more questions. To paraphrase Bob Dylan, ‘something is happening here, but we don’t know what it is.’ Maybe I should re-examine the previous question: Have I given Dr. Mount even one more positive identification of a Copper Age house? No, not YET, but we’re getting there.

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All calibrated dates cited are quoted at the 2σ level of confidence

If anyone reading this recognises a site that they directed, I would be very glad for two things. First, go back to the archive and take another look – could there be any evidence for an elusive Copper Age house? Am I close or way off the mark? Secondly, please consider sending me a copy of the final report, so that the dates and the contextual information can be added to the catalogue.

I should just state, for the record, that I’m not having a bleat about the lack of information provided by the NRA Database (or any of the other sources, either) – I am immensely grateful that such information is available at all in advance of (hopefully) full publication. It is merely my aim to draw attention to the fact that this material is there and may provide some starting points, but that further search and research is required.


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Carey, A. 2002 'Excavations at Knockcarrigeen Hill, Tuam, Co. Galway' Journal of the Galway Archaeological & Historical Society 54, 55-71.

Carlin, N., Clarke, L. & Walsh, F. 2008 'Appendix 1: radiocarbon dates' in Carlin, N., Clarke, L. & Walsh, F. The archaeology of life and death in the Boyne floodplain: the linear landscape of the M4. Dublin, 135-137.

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O'Donoghue, J. 2010 'Archaeological Excavation Report A014-003 - Gortore, Co. Cork. Neolithic house' Eachtra Journal 6, 1-63.

O'Sullivan, J. & Stanley, M. 2005 'Appendix 1 - radiocarbon dates from excavated archaeological sites described in these proceedings' in O'Sullivan, J. & Stanley, M. (eds.) Recent archaeological discoveries on national road schemes 2004. Proceedings of a seminar for the public, Dublin, September 2004. Dublin. 147-154.

Smith, A. G., Pearson, G. W. & Pilcher, J. R. 1971 'Belfast radiocarbon dates III' Radiocarbon 13.1, 103-125.

Smith, A. G., Pearson, G. W. & Pilcher, J. R. 1973 'Belfast radiocarbon dates V' Radiocarbon 15.1, 212-228.

Stanley, M., Danaher, E. & Eogan, J. 2009 'Appendix 1 - radiocarbon dates from excavated archaeological sites described in these proceedings' in Stanley, M., Danaher, E. & Eogan, J. (Eds.) Dining and dwelling: proceedings of a public seminar on archaeological discoveries on national road schemes, August 2008. Dublin, 165-171.

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