1994:095 - LAMBAY ISLAND, Dublin

A second season of excavation was carried out in September. In 1993, cuttings had been opened on both the north-facing (Cutting 2) and south-facing (Cutting 1) sides of a small south-east to north-west tending valley to investigate the date of the working of exposed porphyry faces with debitage below them. Excavation in 1994 was focused on continued work in Cutting 1 and the excavation of a series of 1m sq test pits along the floor of the valley.

Excavation of Cutting 1 in 1993 had shown that there was a mass of porphyry debitage overlying and spreading beyond and to the south of a projecting shelf of bedrock which continues the general line of bedrock from above the cutting. There are definite signs of layering in this material and it overlies a dense mass of stone including a setting of sandstone slabs. Work this year demonstrated that this setting is placed in turn above a depression in the dark loamy matrix in which the stones are set. At the southern end of the cutting the presence of a later stone-filled trench/ditch cut into the stone mass could be recognised. Below the dark loamy matrix, another surface of porphyry debitage is apparent. Evidence that the activity which produced the debitage was prehistoric, and apparently Neolithic in date, is provided by a sealed flint knapping cluster against the base of the rock face as exposed by excavation, and the continued recovery of large quantities of worked flint. All the diagnostic artefacts are Neolithic in date. Along with the flint there were a few small sherds of pottery, numbers of small beach pebbles (some possibly used as hammerstones), sandstone rubbers and cobbles. The cutting was extended to the south and here it would appear that modern agricultural disturbance in the form of the digging of cultivation furrows led to the truncation of the porphyry debitage build-up. But at a depth of only 50–100mm below the surface a dense mass of porphyry occurs. The finds are of a similar Neolithic character to those in Cutting 1.

The test pits, set 10m apart on a line along the floor of valley, were designed to test the extent of modern agricultural disturbance. Cultivation furrows are visible on the surface at the higher south-eastern end of the valley and the valley falls in a series of steps to the north-west where the excavation of Cutting 2 had indicated also the presence of modern cultivation. In all of the five test pits there was evidence of a number of episodes of spade cultivation with cultivation furrows running in different directions. This cultivated soil overlay a more compacted stony surface. At the north-western end of the valley at least, it would appear that material was brought in to increase soil depth and the steps in the valley floor appear to represent the creation of small terraced cultivation areas. In all the test pits there was an occurrence of worked flint. The most significant evidence that the cultivated soil overlies and has disturbed Neolithic features came from Test Pit 2 lying to the north-west of Cutting 1. Here sherds of a decorated Neolithic pot occurred in a stony spread in the lowest part of the cultivated soil and above what appears to be part of a truncated cut feature. This test pit was extended to the west and here part of a feature cut into the pre-cultivation surface and filled with pieces of porphyry was exposed. Lying on the top of the porphyry fill was a flint core, a broken sandstone rubber and a granite hammerstone. Within the porphyry fill and directly below this deposit of three lithic objects is at least one deposit of decorated Neolithic pottery, which was in very poor condition, while at the base of the feature to the north, within a slab setting, part of a Carrowkeel pot was deposited.

The significance of this activity is that it appears to confirm the extraction of porphyry during the Neolithic and suggests that there may have been a range of activities taking place on the site. It is planned that excavation will continue in 1995.