2003:1662 - Site 2C, Magheraboy, Sligo

NMI Burial Excavation Records

County: Sligo Site name: Site 2C, Magheraboy

Sites and Monuments Record No.: N/A Licence number: 03E0538

Author: Ed Danaher, ACS Ltd, Unit 21, Boyne Business Park, Greenhills, Drogheda, Co. Louth.

Site type: Neolithic causewayed enclosure and Iron Age structure

ITM: E 568021m, N 833434m

Latitude, Longitude (decimal degrees): 54.248755, -8.490677

This site was situated within the proposed route of the N4 Sligo Inner Relief Road and County Extension (N4 SIRR). It is located in the townland of Magheraboy to the south-west of Sligo town and is situated towards the eastern quadrant of a large ridge orientated south-west/north-east. It commands panoramic views of Sligo town and the surrounding countryside. Standing at a height of c. 50m above sea level, it is possibly the highest and most prominent point in the region between Knocknarea to the west and Cairns Hill to the east. Test excavations within this area of the proposed route carried out by Frank Ryan in 2001 (Excavations 2001, No. 1176, 01E0942) identified a number of pits with in situ burning and a number of post-holes, indicating probable prehistoric settlement.

Topsoil-stripping carried out during the resolution of the site revealed the foundation trench of a timber palisade with a number of segmented ditches present outside it. These ditch segments ran parallel with much of the palisade, generally at a distance of 3m from it. The palisade and segmented ditches were very similar to features unearthed during the topsoil-stripping of Area 2B, some of which had been truncated by a probable early medieval ringfort, which was excavated by Tara O'Neill (No. 1661 above, 02E0536). Many of the prehistoric features within Site 2B were excavated in conjunction with Site 2C under this licence. These features were located to the south of Area 2C at the southern slope of the ridge. Excavation of the features within both areas revealed that they formed part of a probable Early Neolithic causewayed enclosure which partially enclosed a large area of the ridge, possibly in the region of five acres. No trace of bedding trenches or ditch segments was evident within the eastern extent of the site. The excavation focused on the eastern portion of the site, the remainder lying outside the road-take, with slightly over 2.5 acres of it being excavated; no trace of it was visible prior to excavation.

While the site appears to be principally Neolithic in date, some Iron Age and early medieval features were also discovered. The magnitude of the enclosed space was in direct contrast to the quantity of features contained within it. Due to the size of the site, the exposed features were divided into five zones.

Zone 1
The archaeological remains of this zone consisted of two ditch segments, the bedding trench for a timber palisade, which would have accommodated upright timber posts and planks, and the slot-trenches of a rectangular structure that abutted the palisade. All were excavated into the sandy subsoil. The construction of the palisade at this location was the most elaborate example within the site. From the western limits of the site the course of this c. 37m-long feature headed east-west but, just beyond the halfway point, kinked at a roughly 35¡ angle, altering its route to a north-west/south-eastern one; a post-pit within this trench marked the change in direction (the term 'dog leg' could be used to describe the shape of this feature). The corresponding ditch segment followed a similar path. Part of the western quadrant of this palisade trench was truncated by the ringfort, as mentioned above. The section of palisade located east of the ringfort ditch was the deepest found anywhere on-site, with an average depth of 0.42m; it contained two large post-pits, located c. 1.5m apart, which were probably associated with the post-holes located outside the northern and southern perimeter of the palisade. These would all have combined to form a possible tower/lookout situated north of the causeway that separated the two ditch segments.

The focus of this structure, and possibly this area of the site, appeared to have been the area of marshland to the south, which has been identified as a dried-out prehistoric lake that may have been contemporary with the site. The bedding trench contained post-pits dug into its base, a large quantity of packing stone and a mid-brown silty sandy clay with occasional inclusions of charcoal flecks and pottery sherds. A rectangular structure abutted the south-eastern extent of this palisade and was enclosed by the palisade and ditch segment. The long axis of this structure was aligned north-east/south-west, consisting of a length of c. 14m and width of 4.5m. It comprised three slot-trenches containing packing stone and an entrance located to the north-east; it would have utilised the timber palisade as its southern gable. This structure was very similar in shape and design to many rectangular houses of the Early Neolithic period but, unlike these, did not appear to be a dwelling, as no post-pits or load-bearing elements were present, either within the slot-trenches or the interior of the structure. No signs of either a hearth or floor surfaces were evident. Therefore this structure would have been of light/flimsy construction. The slot-trenches of the rectangular structure had an average width of 0.32m, while their depths ranged from 0.08 to 0.2m.

Of the two ditch segments within this zone, only the full extent of one was exposed, with the remainder of the other lying outside the road-take. A length of 8m of the partially exposed ditch was excavated; it had an average width of 2.1m and a depth of 0.95m. It consisted of steep sides that broke to a slightly concave base, forming a U-shaped profile. It contained seven fills, many of which were variations of mid- to dark-brown silty clay that contained frequent stone inclusions. These stones ranged from pebbles to sub-rounded sandstones with diameters of less than 0.5m. Charcoal lenses and a solitary sherd of Neolithic pottery were also located within the ditch. A distance of over 5.5m separated this ditch from the second ditch segment within this zone. This ditch segment had a length of less than 23m, an average width of 1.6m and a depth of 0.71m. Like the majority of the ditch segments within the site, it ran parallel to the inner palisade, corresponding with any change in direction it may have had. As mentioned above, the palisade within this zone kinked at a 35¡ angle, thus altering its course; this change in direction was also noted in its corresponding ditch segment. The fact that these features respected each other's boundaries suggests that they were most probably contemporary. Six deposits filled this U-shaped ditch segment, while the remnants of a burnt wooden plank were detected directly above its base. The fills varied in colour from grey to dark-brown, the composition of which was mainly silt-clays. Over 300 sherds of Neolithic pottery were present within this, as well as a small number of lithics.

Zone 2
This zone focused on the palisade trench and ditch segments situated to the north of the site. These curved around much of the hill, predominantly in a north-west/south-east direction. The greatest portion of palisade trench and ditch segments was present within this area. Like the ditches, the palisade within this zone was also segmented, with this curvilinear feature comprising five individual bedding trenches. The length of these bedding trenches varied from 8.85 to 15.55m and, together with their associated causeways, had a combined length of less than 90m. The variation in width ranged from 0.2 to 0.5m, with the average being 0.35m; the depth varied from 0.1 to 0.45m, with the average being 0.2m. Steep sides that sloped to a flat to uneven base constituted the cuts for these bedding trenches. Post-pits were present at irregular intervals throughout their extent. It would appear that upright split timber planks occupied the space between these support posts, while packing stones were evident throughout the extent of these bedding trenches. A mid-brown loam deposit was the predominant fill of these five bedding trenches, containing many pebbles, moderate charcoal flecks, occasional flint and chert debitage as well as a flint blade. The remains of a single charred split timber plank were also located within one of these trenches.

The ditch segments within this area could be divided into two groups of three. The first group was comprised of the three larger ditch segments. Segment 1 was 7m long, 1.5m wide and a maximum depth of 0.5m and consisted of steep sides that sloped to a flat base. It contained five fills, with a moderately compact dark-brown silty clay deposit being predominant. Finds included pottery sherds, chert and flint debitage. Whereas the other five ditch segments ran parallel to the palisade (north-west/south-east), segment 1 differed, in that it was mainly orientated east-west, while the palisade trench did not appear to have extended into this area. A shallow subrectangular-shaped pit, 1.1m by 2.2m and with a maximum depth of 0.08m, was located between segments 1 and 2. It appeared to have been deliberately backfilled with a dark-brown clayey silt which contained a few sherds of Early Neolithic pottery, fragments of cremated bone and chert debitage. Ditch segment 2 was situated c. 4m north-west of segment 1 and 9.4m south-east of segment 3.

Ditch segment 3 was the largest of the ditch segments within Zone 2 and was comprised of steep sloping sides, with the north-east-facing side having a greater depth than its south-western counterpart. As with the previous two segments, it had a flat base, but above this base the partial remains of charred split oak planks were present, suggesting that a timber lining might have been present throughout its extent. Three main fills were identified within this feature, with a dark silty clay being the predominant one. This ditch segment contained a large quantity of artefacts, with 141 items being retrieved. The majority were sherds of pottery, but scrapers of chert and flint as well as two arrowheads and the partial remains of a broken stone axe were also present. Charcoal from the basal fill of this ditch segment was dated to 3980-3680 BC. The first of the second group of ditch segments was situated less than 2m north of the north-western extent of segment 3. These three segments could be described as smaller variations of segments 1-3, with their dimensions varying from 3.3 to 4.2m in length, 1 to 1.45m in width and with an average depth of 0.2m

The fills of these features were very similar, consisting of mid-brown silty clay containing frequent small stones, moderate charcoal and occasional artefacts. The artefact assemblage recovered from these segments was similar to that found elsewhere on-site.

Zone 3
This was the interior of the site. Although a large area was enclosed, very few features were evident within the interior, with 43 pits and two possible structures being identified within the enclosure. The foundation trench for one of these structures, the rectangular structure which abutted the palisade trench, has been dealt with under Zone 1. The second possible structure consisted of a series of posts, which were situated near the brow of the hill on the southern side. Although no discernible pattern was readily identifiable from these post-holes, this was the only cluster of its kind within the site. Approximately five of the 43 pits were located on the north-facing slope of the site; the remainder were located on the southern slope and, of these, the majority were concentrated in an area within the south-east quadrant of Zone 3. This area measured 50m by 30m. These pits did not form any discernible pattern but were similar to each other in shape and morphology, with most comprised of steep sides which sloped to a relatively flat base. The dimensions of these features varied from c. 0.4 to 0.9m in diameter and from 0.12 to 0.4m in depth, with the average being slightly in excess of 0.2m. A certain amount of uniformity existed between the fills of these pits, with dark-brown to black silty clay deposits being contained within most. Charcoal inclusions were commonplace, while the vast majority of these pits contained Early Neolithic artefacts, with deliberately broken sherds of pottery being the most abundant find. Other artefacts recovered included arrowheads, scrapers and blades, while chunks of oxidised clay appeared to have been deliberately placed within a number of the pits. Many pits also contained traces of cremated bone, most no greater than 3-5g in weight. These bone fragments are nearly all less than 20mm in diameter. To date, six samples have been identified to species: five pertain to sheep/goat, while one sample is possibly human. Radiocarbon dates of 4240-3700 BC and 3790-3620 BC have been obtained for two of these pits, both of which contained pottery.

Zone 4
This zone focused on the eastern extent of the site, which included a number of Neolithic pits as well as a circular structure of Iron Age date. In total, twelve pits were present within Zone 4. Three small shallow pits orientated in a roughly east-west alignment were the only definite grouping within this zone. Two of these contained sherds of Early Neolithic pottery, and a date of 4220-3700 BC was obtained for one of these. Seven of the remaining pits contained various artefacts, including flint and chert scrapers as well as Early Neolithic pottery; charcoal from the base of one of these pits was dated (calibrated) to 3650-3500 BC. The small circular structure was located close to the eastern excavation limit of the site; this structure comprised a penannular foundation trench with a possible entrance situated to the north-east of it. Charred split oak planks lined the base of this foundation trench, with charcoal from one of these being dated to 370-30 BC.

Zone 5
This delineated the south-eastern extent of the site. Only a small portion of the palisade trench was apparent within this zone, while two ditch segments of varying lengths survived within this area. The foundation trench for the palisade was 6.5m in length, 0.28m wide and 0.25m deep. The morphology of the timber palisade within this zone was different to the rest of the site. Rather than being constructed of post-pits and split timber planks, this foundation trench contained a succession of post-holes, suggesting that the timber palisade would have been comprised of a line of posts set contiguously within the bedding trench. In total, ten post-holes were present within this bedding trench. No signs of repair or reuse were evident within the trench. Within Zone 5, modern disturbance was noted and it is possible that this may have destroyed elements of the palisade within this area. The two ditch segments were somewhat heterogeneous, both in morphology and filling. The smaller of these was 7.2m long, 1m wide and less than 0.5m deep. It contained steep sloping sides that tapered to a rounded base. The length of this ditch was the same as ditch segments 3 and 5 in Zone 2. The more predominant of its two fills was a dark-brown silty clay, with occasional charcoal and small stones, and contained over 160 finds, mainly scraps of pottery and debitage. A number of these finds are worthy of further mention: the remains of a possible cremation, which consisted of an unused flint arrowhead, broken sherds of Neolithic pottery and fragments of cremated bone, was situated to the south-west of the ditch, while, located along the south-facing side of the ditch towards its north-eastern extent, 28 pieces of worked quartz partially encircled a decalcified stone axe (which appears to have been unused) and a fragment of a javelin/arrowhead. As with a large number of the finds retrieved from this site, these items appear to have been ritual deposits. The second ditch segment was located at a distance of 2.4m from the north-eastern extent of the first ditch segment. It was 15.4m in length and had a similar profile to that of the other segment. Contained within the fills of this feature were 107 artefacts, which included pottery, possible hammerstones, worked chert, quartz and flint.

Causewayed enclosures are mainly formed by one or more roughly concentric rings of ditches, frequently broken by causeways of undug soil and with the excavated material piled inside to form a bank. The enclosing element of a number of these sites is added to by the presence of an inner timber palisade/fence. Although the site at Magheraboy does not appear to form a complete circle, other incomplete examples are known, such as at Knaphill in Wiltshire, England (Mercer 1990).

After Donegore Hill in Co. Antrim, this site is only the second known causewayed enclosure in the country. The Donegore site comprises two 'circles' of ditches and an inner palisade, which enclosed an area of about 200m by 150m. Heavy ploughing resulted in the destruction of many of the internal features. Radiocarbon dates indicated prolonged occupation from 4000 BC to 2700 BC (Waddell 1998).

Many theories have been put forward regarding the function of causewayed enclosures, but no universal explanation has been accepted, which means that the excavation evidence from each site has to be examined on its own merits. Places of ceremonial or ritual activity have been put forward as an explanation for many, while cattle-markets and the meeting place of a scattered community have been proposed for others. Places of excarnation, where bodies were exposed to the elements after death until the flesh had rotted away, are a common interpretation for many of these sites. Small pieces of human bone have been identified from the interior as well as from the ditch segments in a number of these sites, such as at Hambledon Hill, Dorset, in England (Mercer 1990).

Mercer, R.J. 1990 Causewayed enclosures. Shire Publications Ltd.
Waddell, J. (1998) The prehistoric archaeology of Ireland. Louth.