1999:256 - LAMBAY ISLAND, Dublin

This site is an important stone axe production site of Neolithic date with a range of associated features. It is the first axe production site recognised in Ireland or Britain where pecking and hammering rather than flaking were the primary methods of working the rock and where there is evidence of grinding and polishing the axe roughouts at the place of production. The rock quarried on the site is porphyritic andesite (porphyry), which forms the sides of two small valleys. The larger and more easterly valley was the initial focus of excavation. Cuttings 1 and 2 and a series of test-pits (14–21) along the bank of porphyry debitage on the east side of the valley indicate that there was a series of extraction and production episodes. From the results of the 1997–8 seasons (Excavations 1997, 57–9; Excavations 1998, 62–5) it is clear that quarrying also took place in a smaller valley immediately to the west.

Excavation on the floor of the eastern valley has been centred on a 20m-by-20m area with the purpose of linking the working areas close to the rock face and the features recognised on the valley floor. In the south of this area, excavation in 1999 focused on uncovering more of what had been initially interpreted as a Neolithic occupation surface. In an excavation area of 9m x 6m this context (C904) was revealed as having a considerable surface expression with a very high density of Neolithic finds of a range of materials. It is now clear that this is not an occupation deposit but a deliberately created low monument with a number of distinct zones recognisable on the surface, including zones of beach pebbles, beach gravel and slabs. This monument appears to cover earlier features and to incorporate features that may initially have been discrete. The most notable of the latter are a number of stone settings in a stratigraphic sequence. These resemble somewhat the settings found at passage tomb complexes, and this analogy is strengthened by the character of some of the material in C904. This includes a fragment of an Orkney-type macehead and two jasper pendants. This area has major potential for the understanding of the sequence and duration of activity on the site. It is also of wider significance because of the complexity of the depositional activities.

At the north end of the 20m-by-20m area, excavation of what had been the major focus of work on the valley floor from 1996 onwards was completed (this is the area around Test-Pit 2, Cuttings 5–8, see Excavations 1996, 36–7, and references above). In the east of this excavation area the original soil, or palaeosol, is partially preserved, in contrast to the western part of the area, where only truncated Neolithic archaeological features cut into the subsoil survive. On the other hand, the palaeosol was very heavily churned around by rabbit burrow activity, and only the stone fills of features retained any integrity in this area. Excavation of F7 and F11, which before excavation were interpreted as being like F1 (a large, stone-filled pit that had a complex series of structured deposits, a radiocarbon date from charcoal in which indicates a date range of 3965–3383 BC), demonstrated that the 'cairn effect' of these features was created by packing stones and sediment into and over scoops/slots dug into the subsoil. There were deposits of cultural material in both of these features. The stretch of foundation trench immediately to the east and north of F7 could be shown to be stratigraphically earlier than F7.

Quarrying of the porphyritic andesite also took place in the small valley to the west of the larger valley that had been the initial focus of the excavation project. Here, excavation of a transect across the valley (Cutting 11) was completed in 1999. From the excavation, it is clear that quarrying of the porphyry here was concentrated on the lower area of the west-facing outcrop. Here a series of major debitage layers could be recognised, with more localised working indicated by less widespread contexts. On the surface of and in one of the major debitage layers, about midway up the stratigraphic sequence of debitage, were clusters of sherds of Early Neolithic carinated bowl pottery, associated with struck flint.

The fieldwork stage of the excavation will be completed in 2000.

Belfield, Dublin 4