2011:626 - GREAT ISLAND, Wexford

Testing was required by Bord Gáis Éireann at Great Island, Campile, as part of pre-development works for a proposed gas pipeline. The proposed pipeline route runs close to two known monuments, lying 25m to the north of the edge of an earthwork, WX039-018(01), described as ‘a subcircular area (dims 55m E–W; 42m N–S) defined by earthen bank, attached to enclosure of church site (SMR WX030-018 (02)). Within were six hollows defined by low banks interpreted as house sites which may have been quarry holes and spoil mounds. Area now levelled and overgrown with some modern quarries.’ A second site, WX039-018(02), is described as ‘early ecclesiastical site and parish church of Kilmokea. Small graveyard with Early Christian cross, circular font of conglomerate and granite cross base. Within circular large enclosure defined by earthen bank. Two bullaun stones associated with enclosure. Horizontal mill found within the enclosure’ (Archaeological Inventory of County Wexford (1996), 117).

The ground where the pipeline is proposed to run closest to the enclosure (WX039-018/01) is flat and low-lying and formerly subject to tidal flooding. The first-edition OS map shows this area as marshy. The land was a tidal marsh prior to reclamation and the monastic site appears originally to have lain close to the water’s edge. The marsh was reclaimed in the second half of the 19th century by the creation of levees on the banks of the River Barrow. The low-lying marsh was then drained by a series of rectilinear drainage ditches. The flood defences failed and the land was again flooded in the 1950s when reinforcement and raising of the levees took place and new drainage ditches were excavated.

It was initially proposed to excavate a single linear trench with offsets. The results of the first trench led to modification of the plan, as the long trenches within the marshy ground were both impractical and dangerous. The marshy ground was said by the landowners to be at an optimum level of dryness, following a summer with lower than normal rainfall; nevertheless, prolonged use of the mechanical excavator caused the machine to sink. It was decided to excavate a series of smaller pits in the swampy area, owing to the risk to the machine, the depths requiring excavation and the speed at which the trenches began to fill with water. A linear trench, 1.5m wide and 0.35m deep, was excavated from 10m to the north of the outline of the D-shaped enclosure (WX039-018/01), which could easily be seen as a cropmark (a semicircle of richer green grass). The land sloped northwards and eastwards from this point. The first c. 10m was a dark brown/grey mineral soil with stone, but as the ground became level the mineral soil gave way to grey compact clay. The limits of the former marshy ground were thus apparent.

The other trenches were excavated within the former marsh. The results replicated the evidence from the western end of Trench 1. A homogeneous grey clay lay beneath a shallow skin of sod and topsoil, c. 0.07m deep.

In one trench, however, the clay overlay a layer of peat-like organic material, composed mainly of fragments of reed and rushes. Logs of spruce/pine wood were incorporated in the organic material, indicating that the material is of recent origin, possibly deposited deliberately as part of land reclamation. At a depth of over 1m the organic material overlay grey/black estuarine silts. This was removed to a depth of 2.5m and it continued below this depth.

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