Introduction – 2015-16 Fieldwork – IRLL15 Map – Giant's Leap chert quarry – The Team

Introduction

The Returning to the Source project is the second part of the Irish Lithics Landscapes project (IRLL) that is investigating the places where prehistoric communities obtained the raw materials for their flaked stone tools during the Irish Mesolithic, Neolithic, and Early Bronze Age, which dates to about 8,000–2,000 BC. During the first part of the project that was based at the Université de Montréal, we focused attention particularly on chert from northwest Ireland; during the second part, based at the University College Dublin, we turned attention to the flint deposits from the northeast of the island, along with an island-wide flint beach pebble survey, and a continuation of the chert deposits in the west of Ireland (for the differences between chert and flint see Driscoll et al. 2016).

Glenarm Quarry of the Ulster White Limestone Formation with courses of flint nodules visible.

2015-16 Fieldwork

For the project's geological prospection we spent c.350 person/hrs collecting 300 geological hand samples in the three zones - 1. in the northeast of the island of Ireland collecting samples from the flint deposits in the Ulster White Limestone Formation; 2. along the coast for an island-wide flint beach pebble survey; 3. in the west of Ireland collecting samples from the chert deposits in the Burren area in particular. The fieldwork recording and the laboratory analytical methods follow the same methods as the previous project.

NE Ireland flint deposits. The first component of the geological prospection focused attention on the in situ flint from outcrops in northeast Ireland, with the flint often called 'Anrim flint'. In the northeast, we examined 33 outcrop groups from three counties. The flint from the northeast is derived from the Ulster White Limestone Formation; compared to the chert-bearing rock units surveyed in the previous project which form part of the Carboniferous Basin of Ireland, the flint-bearing Ulster White Limestone Formation outcrops are more constrained to thinner strips of outcrop beneath the basalt cap (darker rock above the paler limestone in image). The Ulster White Limestone was previously more extensive across the island of Ireland, but survives today mainly along the Antrim coast partly due to this basalt cap which protected it from erosion. While the outcrops in the northeast are horizontally constrained, vertically the exposures are formed as cliffs that can best be described as intimidating to survey in many cases. This image on the right shows a sea cliff on the upper left, and on the upper right a typical nodule sampled from a vast slipped block, while the bottom shows an example of a massive nodule exposed in a quarry face where a vertical sequence of 15 courses of nodules were sampled (marked in red): an even larger flint nodule - (a paramoudra) - can be seen in the middle of the exposure towards the right. This paramoudra is from the disused Clarehill Quarry, in the area where the word paramoudra for these very large flint nodules is derived; the term was first used by Buckland in 1817 and is a corruption of a Gaelic name, probably padhramoudras "ugly Paddies" or peura muireach "sea pears" (Porter).

Flint pebble beach survey. Along with the geological survey of the in situ flint in outcrops, we undertook a series of beach surveys around the island, investigating the distribution of flint pebbles. This map shows the distribution of beach flint according to Woodman et al. 2006), with this project's survey points marked in red, and the in situ flint deposits of the Ulster White Limestone Formation. In total, 44 beaches were surveyed. The choice of beaches was guided by Woodman et al.'s (2006) schematic, which suggests that beach flint is available along the east and south coast, and then available on some beaches along the west and north coast. In order to quantify this distribution of beach flint, 13 areas outside of the northeast were surveyed, with at least three beaches surveyed in each area (three areas had four beaches in total surveyed), thus surveying 42 beaches; these all fell within the Woodman et al.'s suggested distribution, except for one extra area in the southwest which was also surveyed. As well as the beaches away from the flint deposits, two beaches in the northeast close to outcrops with flint were surveyed in order to provide a baseline to compare the quantity and size range of beach flint on beaches near flint outcrops to those away from the outcrops.

Burren chert deposits. The final component continued the chert provenancing of the previous project, extending the survey south into south Galway and Clare, with a particular focus on the chert outcrops of the Burren, but also including a number of outcrops surveyed in south Galway and across the River Shannon into County Tipperary.

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IRLL15 Map

The map below provides an overview of the IRLL15 geological prospection, and contains two layers: a survey point layer that includes survey points with and without sampled material (i.e. negative evidence of survey points with no in situ chert / outcrops not found), and a sample layer with all the geological samples collected that also includes descriptions of the samples' survey points. The layers can be toggled using the layer box on the left, or the map can be opened in a new window and layers toggled from there.

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Giant's Leap prehistoric chert quarry, Burren, Cavan

Towards the end of the project we were invited by Séamus Ó hUltacháin to examine a possible chert quarry in the Burren, Co. Cavan. Since 1997 local historians Séamus and Gaby Burns have been studying the landscape now known as The Cavan Burren – a limestone escarpment north-west of Cuilcagh Mountain, with Burren townland at its core. During the course of the survey an integrated prehistoric complex of field walls, hut sites, rock art and humanly modified glacial erratics began to emerge. While visiting the area in 2008 to verify the work done on glacial erratics, Dr. Emmanuel Mens remarked to Séamus on the abundance of ‘good quality’ chert in the limestone cliffs – stating that it almost certainly would have been utilised in prehistory.

Subsequently, and with the help of geologist Dr. Kirstin Lemon, Séamus set about looking for evidence. A number of sites in Burren and the adjacent townlands seemed to suggest chert extraction – cliff recesses, pits etc. The most obvious seemed to be in Giant’s Leap – a gorge in Burren, where not only did the cliffs appear recessed but a roof support column remained. On the opposite cliff to ‘the mine’ a ‘work platform’ seemed to suggest extraction of large chert nodules. In 2017 Killian Driscoll visited the site and confirmed Giant’s Leap as a prehistoric chert extraction site.

The quarry faces. The quarry is located at the base of a 6 m high NE-facing limestone outcrop that runs NW-SE in a narrow gap called Giant’s Leap. The outcrop is of the Dartry Limestone Formation, which commonly has good quality chert (Driscoll et al. 2016, Harney et al. 1996). At the point of the quarry, the limestone outcrop has multiple layers of chert at the base where the outcrop was quarried with the further layers above the quarried section. The quarry face is c. 4.3 m wide, with a central pillar that is c. 0.5 m wide at its base. The central pillar is c. 1 m deep within the quarry. The NW recess is c. 4 m deep and c. 1.1 m high, and the SE recess is c. 1.6 m deep and c. 0.8 m high. A second quarry is located along the same outcrop, c. 10 m to the WNW. This quarry is smaller, without a central pillar. It is at the base of the c. 6 m high outcrop, and is c. 2.4 m wide, c 2.8 m deep, and c. 1.3 m high. The chert layers at this point of the outcrop are - due to the bedding dip of the limestone and chert layers - the chert layers that are located above the quarry with the central pillar.

Nearby monuments. The quarry sits among a series of prehistoric monuments including different types of megalithic monuments, rock art sites, mounds, and enclosures. The closest monument is a wedge tomb on a hilltop 65 m to the SSW (SMR CV004-005). An unclassified megalithic tomb (CV004-027) lies 385 m to the SSW, with cremated human bone dating to 2438-2200 cal BC 385 that was recovered as a result of animal activity at the tomb in 2014. A portal tomb lies 385 m to the WSW (CV004-004). A group of rock art sites lie 265 m to the west (CV004-051 to CV004-055). A burnt mound lies 365 m to the NW (CV004-065). An inland promontory fort lies 265 m to the north (CV004-036). A court tomb and nearby enclosure lie 445 m to the SE (CV004-009).

Other prehistoric quarries in Ireland and Northern Ireland. There are very few prehistoric quarries identified to date on the island of Ireland. In Northern Ireland there are two flint and two porcellanite quarries identified. The flint quarries are an open cast flint mine at Ballygalley, Co. Antrim (Collins 1978, NISMR 2020a), and a flint quarry at Ballycoos, Co. Antrim (NISMR 2020b). The two quarries for porcellanite stone axes are in Tievebulliagh, Co. Antrim, and on Rathlin Island (Jope et al. 1952).

In the Republic of Ireland, there is a porphyry stone axe quarry on Lambay Island, Co. Dublin (SMR DU009-001016) (Cooney 2005), and a rhyolite quarry (possibly for flaked stone tools and axes) in Monvoy, Co. Waterford (SMR WA026-078) (Green and Zvelebil 1990, Zvelebil et al. 1989).

A chert quarry is located on Knockeyon overlooking Lough Derravaragh (O’Sullivan et al. 2007). This limestone outcrop exposes the Derravaragh Cherts, which contains chert called ‘festooned chert’ which often has distinctive fine pressure solution lines, thus producing ‘festooning’. The Derravaragh Cherts is limited to an area of less than 200 km2 in central Ireland (Morris et al. 2003).

A probable chert quarry site has been identified in Co. Sligo, on the northern slopes of Knocknarea. This site is listed in the SMR as a lithic scatter (SMR SL014-277), and records thousands of lithics found on the hillside close to many outcrops of chert-bearing Dartry Limestone Formation (Bergh 2009, Harney et al. 1996). While this is a probable chert quarry site, no actual quarrying has been identified on the outcrop faces (Bergh 2009).

Geological samples taken. Two samples were taken from the quarry with central pillar. Sample IRLL15299 was taken from the NNW-facing face in left chamber, and IRLL15300 was taken from outside and 0.5 m above the quarry face. One sample (Sample IRLL15301) was taken from the smaller quarry face 10 m the WNW. A further two samples (Samples IRLL15297 and IRLL15298) were taken from an outcrop c. 300 north the the quarries.

References

Bergh, S. 2009. Black is the Colour. Chert, concave scrapers and passage tombs. In G. Cooney, B. O’Connor, J. Chapman (eds), Materialitas: working stone, carving identity. Prehistoric Society Research Papers 3. Oxford: The Prehistoric Society and Oxbow Books, 105-112.
Collins, A.E.P., 1978. Excavations on Ballygalley Hill, County Antrim. Ulster Journal of Archaeology 41, 15-32. Retrieved February 12, 2020, from www.jstor.org/stable/20567803.
Cooney, G. 2005. Stereo porphyry: Quarrying and deposition on Lambay Island, Ireland. In Topping, P., and Lynott, M. (eds), The cultural landscape of prehistoric mines. Oxford: Oxbow Books, 14-29.
Driscoll, K., Burke, A. L., Warren, G. M. 2016. Introducing LIR (Lithotheque Ireland), a reference collection of flaked stone tool raw materials from Ireland. Journal of Lithic Studies, 3(2). doi.org/10.2218/jls.v3i2.1444.
Green, S. W., Zvelebil, M. 1990. The Mesolithic colonisation and agricultural transition of south-east Ireland. Proceedings of the Prehistoric Society, 56, 57–88.
Harney, S., Long, C. B., MacDermot, C. V. 1996. Geology of Sligo - Leitrim: A Geological Description of Sligo, Leitrim and adjoining parts of Cavan, Fermanagh, Mayo and Roscommon, with accompanying Bedrock Geology 1:100,000 Scale Map, Sheet 7, Sligo - Leitrim. Dublin: Geological Survey of Ireland.
Jope, E., Morey, J., Sabine, P. 1952. Porcellanite Axes from Factories in North-East Ireland: Tievebulliagh and Rathlin. Ulster Journal of Archaeology, 15, 31-60. Retrieved February 10, 2020, from www.jstor.org/stable/20566647.
Morris, J.H., Somerville, I.D., MacDermot, C.V., 2003. Geology of Longford and Roscommon: A Geological Description, with accompanying Bedrock Geology 1:100,000 Scale Map, Sheet 12, Longford - Roscommon. Dubin: Geological Survey of Ireland.
NISMR. 2020a. Open Cast Flint Mine, SMR Number ANT 035:039. Retrieved February 12, 2020, from apps.communities-ni.gov.uk/NISMR-PUBLIC/Details.aspx?MonID=2432.
NISMR. 2020b. Prehistoric Flint Quarry, SMR Number ANT 035:061. Retrieved February 12, 2020, from apps.communities-ni.gov.uk/NISMR-PUBLIC/Details.aspx?MonID=2454.
O’Sullivan, A., Little, A.Parkes, M. 2007. The power of stone. Archaeology Ireland 21(3), 36–9. Retrieved February 17, 2020, from www.jstor.org/stable/20617848.
Zvelebil, M., Moth, E., Peterson, J. 1989. 1989:096 - Monvoy, Waterford. Retrieved February 10, 2020, from excavations.ie/report/1989/Waterford/0000930.

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The Team

Principal Investigator

Killian Driscoll, UCD School of Archaeology, University College Dublin

Investigators

Adrian Burke, Département d'anthropologie, Université de Montréal
Gabriel Cooney, UCD School of Archaeology, University College Dublin
Xavier Mangado, Seminari d’Estudis i Recerques Prehistòriques (SERP), Departament de Prehistòria, Història Antiga i Arqueologia, Universitat de Barcelona
Mar Rey, Seminari d’Estudis i Recerques Prehistòriques (SERP), Departament de Prehistòria, Història Antiga i Arqueologia, Universitat de Barcelona
Graeme Warren, UCD School of Archaeology, University College Dublin

Acknowledgments

Killian Driscoll was awarded a two year Government of Ireland Postdoctoral Fellowship to undertake this research project at University College Dublin, and the laboratory analysis is part funded by the Spanish Ministry of Economy, Industry and Competitiveness (HAR 2014- 55131).