2024:816 - Regles SHD Area B, Lusk, Dublin

Excavation of a large, outsized pit feature/well C.11, was undertaken. This was a funnel-shaped cut of an irregular, sub-oval shape on a northeast-southwest orientation,  measuring 7m x 5.5m at ground level, with a gradually sloping north-eastern end. The cut descended to the deepest point of the pit, which was at 2.3m in depth below the surface level. On plan the deepest part of C.11 was a sub-circular area 2.1m in diameter, off-centre and to the southwest of the middle of C.11. The north-western, south-western and south-eastern sides of C.11 all sloped in a steeper, more direct fashion into the cut’s deepest point at 21.56m OD, 2.3m below the surrounding ground level. The more gently sloping north-eastern side of C.11 was covered by what appeared to be a deliberately deposited layer, C.18, which may have been formed by upcast from the deeper element of C.11,  or alternatively C.18 may have been the result of the use of this gently sloping side of C.11 to access the deeper aspect of the pit, resulting in a certain amount of churn and foot trample forming the layer. C.35 was the primary fill of the deepest part of C.11, comprising a reasonably compact, dark grey silty clay, with some occasional unburnt stone inclusions. Rather than C.35 being a deliberate deposit it would appear to have accumulated through natural silting and thus it was possibly reflective of the abandonment of C.11 or the fulfilment of the outsized pit’s original purpose or indeed the passage of time during which the pit was used, potentially as a water source. C.35 was dated to 1731-1517 Cal. BC.

The second phase of activity at the site appeared to be incidental and subsequent to the cutting of C.11 and the deposition of C.35 into that cut, with this later phase of activity commencing with the deposition of C.27/29, which was a relatively deep (0.6m) and concentrated deposit of dark brown-black, charcoal and burnt stone-rich silty clay. C.27, which was dated to 1731-1516 Cal. BC, and was the direct product of the use of pyrolithic technology to heat water; however, it is suggested that an unfeasibly large episode of such activity would be required to raise the temperature of any water contained in C.11 by a single degree Celsius. Therefore, it makes sense that the water which was being heated at this site by pyrolithic means was not contained in C.11, but perhaps the latter may have been the source of the water used.

It is possible therefore that the ultimate layer which was reflective of pyrolithic activity, C.21, which was a loose dark brown silty clay with frequent burnt stone inclusions, may have occurred at the site following that lengthy period of abandonment which was evidenced by the intervening fills, C.19, C.20 & C.12, but it is equally possible that C.21 may have been introduced into C.11 at this later point in time in the stratigraphic sequence in an effort to level the surrounding piles of spent pyrolithic materials, which were doubtless around C.11 or indeed an attempt to deliberately backfill C.11 itself. The upper fill of C.11 was C.22, which was another peaty dark brown-red silty clay layer reflective of the final abandonment and filling of C.11.

The remaining excavated features at the site comprised C.4 (a possible trough setting) and a number of small pits which were filled with charcoal-rich burnt stone materials.