2000:0463 - BALLYSAXHILLS, Kildare

A multi-stage programme of archaeological assessment and investigation was undertaken at the site of the proposed extension to the Kilsaran Concrete Ltd Sand and Gravel quarry and is ongoing at the time of writing. Previous programmes of geophysical survey, test excavation and monitoring of topsoil-stripping at the Stage 1 and Stage 2 areas of the proposed quarry expansion, carried out by Margaret Gowen (Excavations 1995, 43–4, Excavations 1996, 49, 95E0256) and Leo Swan (Excavations 1999, 121, 99E0704), had revealed no archaeologically significant material. The current programme of investigation is concerned with Stage 3 of the proposed quarry expansion, an area of approximately 2.5ha set on steeply sloping west-facing pasture on a sand-and-gravel ridge.

Detailed gradiometer survey was undertaken across the entire area by GSB Prospection under detection device licence 00R003. Anomalies of archaeological potential were identified mainly in the eastern part of the survey area, where they were seen to coincide with a level area in the highest part of the field.

Test excavation undertaken from 4 to 14 September 2000 investigated all geophysical anomalies identified as being of archaeological potential, with a particular emphasis on the eastern part of the field. Test-trenching indicated that the majority of these anomalies represented natural variations in the subsoil or recent land improvement activity. However, one subcircular anomaly of 20m by 25m extent appeared to represent a shallow, irregular, 1m-wide ditch, which apparently enclosed a number of features, one of which produced two sherds of prehistoric pottery.

In discussion with the relevant Archaeological Officers of Dúchas The Heritage Service and Kilsaran Concrete Ltd, it was decided to proceed with total excavation of the area of the subcircular geophysical anomaly and several other nearby anomalies not identified by the testing programme. A stepped area of 825m2, measuring 35m east-north-east/west-south-west by 30m, was fully excavated between 24 September and 25 November 2000.

It was apparent from scarped surfaces, modern plough furrows and in situ root burning noted during the course of the excavation that land improvement works had substantially disturbed the site. This observation was supported by information provided by the previous landowner, who recalled the field being levelled by a bulldozer as part of land improvement works at the beginning of the 1970s, followed by a programme of deep ploughing. This had resulted in substantial disturbance and removal of archaeological material, making interpretation of the site problematic.

The excavation programme failed to confirm the existence of the subcircular ditch provisionally identified by geophysical survey and test-trenching. During the excavation the feature proved difficult to identify in plan, ranging in width from c. 0.7m to 1.5m and from 0.1m to 0.8m in visible depth. Ditch profiles ranged from shallow curving dips to a steep-sided U-shape, with frequently abrupt transitions. Once the fill had been removed and exploratory sections cut through the base, it became apparent that this feature constituted a curving linear depression or channel of natural origin, apparently formed by a localised slump in the underlying layers of sand and gravel. The apparent fill overlying this unusual natural feature could therefore be interpreted as topsoil that had not been disturbed during reclamation efforts. This interpretation was verified during the subsequent monitoring programme (see below), when machine removal of subsoil showed the same narrow slump in natural layers of sand and gravel extending up to 2m below the interface of topsoil and subsoil.

Despite the subcircular anomaly proving to be natural in origin, a number of prehistoric features were identified within the area of the excavation. A short, steep-sided trench containing a flint thumbnail scraper and several sherds of prehistoric pottery was identified immediately inside the arc of the natural channel. A single, substantial, rectangular post-hole was identified within this trench, from which sherds of prehistoric pottery were recovered. Several small post- and stake-holes were identified in the vicinity of this trench. These features did not form any clearly identifiable structure. Some areas of limited burning were identified across the site, but nothing that could be interpreted as representing a hearth.

Finds from the excavation include a fine chert leaf-shaped arrowhead, an unfinished flint projectile point, eight flint thumbnail scrapers and a single-edged flint knife or scraper. In addition some 40 apparent waste pieces of flint and chert were identified. All of these lithics were recovered from layers apparently disturbed by the land improvement works. Also recovered from these disturbed layers were a number of small, extremely fragile pottery sherds with a range of forms and fabrics, all but one of apparent prehistoric date. The single exception was a heavily abraded glazed sherd apparently of medieval date, located within an area of deep plough furrows.

All of the pottery recovered from secure contexts appears to be prehistoric in date with a wide range of fabrics. Although the pottery has not yet been examined by a specialist, and no obviously diagnostic forms or decoration have been recovered, the fabric appears to fit well with a broadly Neolithic date, a conclusion supported by the range of lithics. Finds, structural elements and archaeological layers all seem to be concentrated in an area at the south of the site. The function of the site remains unclear.

Monitoring of topsoil-stripping in a 15m-wide area running along the eastern edge of the Stage 3 expansion area was undertaken in November and December 2000. A single sherd of prehistoric pottery was recovered from disturbed topsoil, but no other features or deposits of archaeological significance were noted. Monitoring of topsoil-stripping in the remainder of the Stage 3 area commenced in February 2001 and is ongoing at the time of writing. A number of prehistoric features were identified in the area of the excavation, including a shallow pit containing a polished stone axe and several flint scrapers. These findings will be presented in Excavations 2001.

32 Fitzwilliam Place, Dublin 2