2009:394 - DUNLO, Galway

Excavation and monitoring was carried out in Dunlo townland, Ballinasloe, Co. Galway, between March and April 2009. The work was undertaken for Precision Construction Ltd on behalf of Tesco Ireland Ltd. The development was close to a number of
monuments, a post-medieval canal, associated buildings and features (GA088–010) and the site of an enclosure (GA088–028). An assessment and geophysical survey were sought in advance of a planning application for the proposed development.
A previously unrecorded archaeological site was discovered in Field No. 7. A programme of testing was recommended throughout the entire site to include specific anomalies identified in the geophysical survey. The anomaly identified was confirmed to be a burnt mound. Full excavation of the fulacht fiadh (Site 1) was undertaken in tandem with a programme of monitoring of topsoil-stripping across the entire development site. During the course of monitoring three additional sites of archaeological interest were uncovered, an ironworking site (Site 2), deposits of burnt-stone material (Site 3) and a burnt spread (Site 4). Each of these additional sites were fully excavated. Site 1, fulacht fiadh Excavation of the fulacht fiadh was conducted between March and April 2009 and revealed a large subcircular mound with frequent burnt stone, ash and charcoal-enriched soil which measured 21.5m north–south by 18.6m wide and 0.8m deep. Several layers of burnt-mound material were identified; the main deposit (Context 3) comprised moderately compacted greyish-black sandy silt with much burnt stone and charcoal which measured 10m north–south by 10m wide and 0.6m deep. The stones comprising Context 29 were notably larger and less fragmentary than those in Context 3. Context 29 may represent a different phase, perhaps a supply of stones that were
stored to be reused in the trough at a later stage.
Occasional deposits of peat and clay were visible in the sections over and above these mound fills, which suggested that there were periods when the site, or areas of the site, was not in use, thus allowing the
peat to form.
Several additional features were uncovered
including cultivation furrows which traversed the top of the mound in an east to west orientation. Most notable amongst these was Feature 4, a sub-oval pit filled with dark-brown silt with much burnt stone
and moderate amounts of charcoal. The fragmented corroded remains of a possible iron blade were found in the pit. Feature 4 measured 3.2m north–south by 1.5m wide and 0.27m deep. The trough feature was found directly below this pit.
The trough consisted of a subrectangular-shaped wooden structure measuring 2.85m south-west to north-east by 1.5m wide and 0.55m maximum depth.
The trough was constructed of horizontally placed rods which were held in place at intervals by weaving them around vertical wooden stakes, with the worked
end driven into the ground. The rods measured between 2m and 0.3m in length. In between the horizontally placed rods were twigs and a matrix of dark-black fine-grained silt. The north-eastern interior wall of the trough structure was intricately constructed of horizontally interweaving rods and sails to form a basket-like lining. At the southwestern end of the trough was a large horizontally placed flat piece of timber 2.25m in length, 0.24m wide and 0.05m. This piece may have acted as a shelf or possibly as a step; it may also have functioned as an additional support for the south-western end of the structure that did not survive well and collapsed under the weight of the surrounding gley. The southwestern end of the trough was also constructed of interweaved rods and sails similar to the corresponding north-eastern end. Some pieces of wood lining had evidence of charring and there were occasional randomly found pieces that had worked ends. The trough was filled with moderately compacted mid-grey material of burnt stones, finegrained silt and charcoal.
The structure was contained within a large
subcircular cut that had been dug into the
surrounding gley natural and measured 3.8m north–south by 3.75m wide and 1m deep. The sides of the pit were gradually sloped and stepped in profile on all sides. The base was subrectangularshaped and relatively flat; it measured 2.2m southwest to north-east by 1.5m wide. The trough frequently filled with groundwater. Some moss lining was present in-between interweaved wood that lined the north-eastern interior of the trough. There was no
wood lining the base of the trough.
Surrounding the area where the trough was
located a deposit of heavily compacted light-yellow clay had accumulated which measured 10m west–east by 4m wide and had a maximum depth of 0.25m. This was likely to be upcast material resulting from digging of the trough pit, which was subsequently deposited in the vicinity. Radiocarbondating of a sample of charcoal from mound material dated the fulacht fiadh to 1259–1000 cal BC. A further charcoal sample taken from the basal fill of the trough dated the feature to 1112–901 cal BC.
Site 2, ironworking site
Site 2 was identified during monitoring of topsoilstripping south-west of the site compound where a proposed topsoil storage area was located. The overall excavation area measured 10m east–west by 4.5m wide. The site consisted of five pits (Features 1–5) excavated into the surrounding mid-orange sandy boulder clay. Feature 1 consisted of a large subcircular pit which abutted a large boulder. It measured 1.35m north–south by 0.95m wide, and had a maximum depth of 0.18m. The fill consisted of 0.15m depth of moderately loose light-brown sandy clayey silt with moderate charcoal and slag inclusions, which overlay 0.03m of moderately compacted charcoal-enriched silt with occasional small pebbles. The cut of the pit was shallow with gently sloping sides and a flat base. Feature 1 was compatible with being a smithing hearth or a charcoal-making pit. However, the large boulder suggested it might have been employed as an anvil associated with a smithing hearth.
Feature 2 consisted of a shallow deposit of darkbrownish-black charcoal-enriched sandy clayey silt with frequent charcoal and occasional slag inclusions which was contained within a shallow irregularshaped
cut. It measured 1m north-east to south-west by 0.3m wide and 0.1m deep. Feature 3 consisted of a sub-oval pit which contained a singular fill of midorangey-
brown silty sand with frequent charcoal and
slag inclusions. It measured 0.7m north–south by 0.42m wide and 0.12m deep. This feature may have been a slag pit furnace pit.
Feature 4 consisted of a subrectangular pit with a single fill of moderately loose black charcoalenriched sandy clayey silt and with frequent slag inclusions, contained within a steep-sided slightly concave-shaped cut that measured 1.25m north-west to south-east by 0.65m wide and 0.15m deep. It contained a large amount of smithing waste and, similar to Feature 2, both features were likely to have had smithing material enter the cuts on abandonment. Both features may have been charcoalmaking
pits supplying the two smelting furnaces
(Features 3 and 5). Feature 5 consisted of a subcircular pit that was filled by loosely compacted mid-brownish-grey silty sandy clay with moderate slag inclusions and contained within a gently sloping cut with an uneven base. It measured 0.56m east–west by 0.53m wide.
This feature may well have been the basal pit of a slag pit iron-smelting furnace, as it contained a small amount of smelting residue. Radiocarbon-dating of a sample of charcoal from the upper fill of Feature 1 dated the site to cal AD 985–1028. Evaluation of the archaeometallurgical
residues from the site concluded that it was most likely to be a small iron-production site where both iron smelting and iron smithing occurred; of that smithing it is likely to be bloomsmithing. No assemblage of smithing floor material from bloomsmithing has been previously examined in detail in Ireland.
Site 3, deposits of burnt-stone material
Site 3 was identified during monitoring of topsoilstripping north-west of the fulacht fiadh (Site 1). Site 3 consisted of two features, both of which consisted
of subcircular deposits of burnt-stone material 1m apart which lay below up to 1m of overlying topsoil and peat. The overall excavation area measured 4m north–south by 3.5m wide. Feature 1 consisted of loose mid-greyish-brown peat with moderate charcoal and ash inclusions, as well as many small burnt-stone fragments. It measured 1.5m north–south by 1.32m wide and 0.12m deep. Feature 2 consisted of a deposit of loose mid-grey/dark-brown peat with moderate charcoal and frequent small burnt stones. It measured 1.4m north west/south-east by 0.95m wide, and 0.1m deep. There were no visible cuts for either feature and no obvious function for their use.
Site 4, burnt spread
Site 4 was identified during monitoring of topsoilstripping at the base of a gentle slope, in marginal land c. 25m south of the peaty wetland location of the fulacht fiadh. It consisted of an irregular-shaped spread of material comprising frequent small firecracked stones in a charcoal-enriched clayey silt matrix. Overlaying the burnt spread was 0.4m of
topsoil and silty clay with frequent inclusions of modern glass shards, pottery sherds and fragments of corroded metal.
The spread (Feature 1) was composed of primary material which measured 15.6m east–west by 8.75m wide and had a maximum depth of 0.2m. It consisted
of moderate to firmly compacted mid-greyish-black soil which comprised 80% burnt-stone fragments and grains and 20% sandy silt with frequent charcoal
inclusions. The site was heavily truncated by modern cultivation furrows, field boundaries and drains which traversed the site in an east to west orientation.
A large field boundary (Feature 2) truncated the site and consisted of medium sub-angular and subrounded stones contained within a shallow U-shaped cut within a mid-brown clay matrix. It measured 12m
east–west by 1.75m wide and 0.4m deep. A stone filled drain (Feature 3) truncated the site in a north–south direction and measured 5m north–south by 0.45m wide and 0.2m deep. This drain abutted
Feature 2, suggesting that both features were contemporary. Similar stone-filled drains also traversed the nearby fulacht fiadh and the surrounding fields. A large sub-oval pit (Feature 4) was located towards the centre of the burnt spread. It contained three overlying fills within a steep-sided cut with a concave base. The pit measured 1.7m east–west by 1.5m wide and 0.55m deep. The various fills had moderate to frequent burnt stone and charcoal inclusions. The pit filled with groundwater during excavation. It may have been a former trough feature. Radiocarbon-dating of a sample of charcoal from the main mound context dated the site to 507–386 cal BC.