2012:148 - Eleven Ballyboes, Donegal

Over the last decade, a large quantity (c. 1500 items) of lithic material has been recovered by local collectors from the intertidal zone of two small bays in Eleven Ballyboes townland, Co. Donegal. Based on typology, this material appears to date from the Early Mesolithic. At this time, sea-levels were lower, possibly by as much 10m, transforming the area from a marine shoreline into an estuarine or riverside locale. It had been hypothesised that the lithics are eroding out of a submerged deposit and washing ashore. This was confirmed by fieldwork in 2011 which found no source for the lithics within the beach or backing area of land (Excavations 2011, No. 145). The 2011 field season was however unable to locate the source deposit.

In summer 2012, further fieldwork (swimover surveys, hand coring and excavation of 5 test pits) was conducted in the subtidal zone of the western bay in an attempt to locate the submerged source deposit and verify if in situ material was still present. Both the non-intrusive swimsover and excavation were successful in locating struck flints on, or buried within, the seabed. In total, 37 lithics were collected from the seabed surface by the swimsover while 8 lithics and up to 25 small (<10mm) possible debitage flakes were excavated from the test pits. All the lithic material concentrated in shallow water (<2m depth) within 50m of the shoreline with a cluster in the centre of the bay c. 20-30m off the shoreline. While it has been possible to demonstrate that prehistoric material is present underwater, it is still unclear whether it is coming from an in situ deposit. The fact that several of the subtidal lithics (including the majority of the excavated finds) are much fresher than the intertidal ones, characterized by sharp edges, distinct scars, the lack of white, yellow or orange patination and a distinctive light to dark blue-grey colour, could be taken as supporting evidence. However, their context of discovery - a poorly sorted gravel layer with broken shell fragments – is not the typical environment in which one would expect in situ preservation. Further investigations to collect a larger sample of artefacts and to examine their stratigraphic position would be needed to determine the precise nature of the source deposit. Three additional test pits were dug in the intertidal zone of the eastern bay and revealed little except a few water-rolled lithics within reworked beach sediment. However, swimover surveys within this bay revealed a layer of peat within in situ preserved wood in shallow water (c. 1-2m depth). Peat samples taken by hand cores have been radiocarbon dated and provided dates of 8693–8985 cal BP and 9406–9308 cal BP for the top and bottom of the peat respectively. These dates broadly coincide with the independent typological attribution of the lithics to the Early Mesolithic. However, no lithics or other archaeological material has been found to date which is in direct association with the peat. Further survey and excavation of the peat layer would be necessary to directly confirm if there is any archaeological material buried within it and also to obtain samples for palaeo-environmental analysis. Finally, in additional to the prehistoric material, swimover surveys conducted in deeper water (c. 9m water depth) immediately adjacent to the two bays located a small (1.4 x 0.25m) cannon on the seabed. This appears to be an isolated find with no other associated wreck material visible on the seabed.

Centre for Maritime Archaeology, University of Ulster, Coleraine BT52 1SA, and Peter Woodman, University College Cork, Cork