Burnt mound in Portmarnock

The results of this excavation were summarised by Gill McLoughlin as follows; 'Area 5 was located towards the east end of the sewer pipeline to the Coast Road and comprised a large suboval or keyhole shaped pit (C61). The pit was filled with black soil containing charcoal and burnt stones and is most likely to have been associated with a burnt mound of which no further trace was found. It is possible that remnants of a burnt mound could remain outside of the area of the pipeline. The full extent of the pit was not excavated as it extended north beyond the limit of the trench required for the pipeline. Excavation of this area took place over five days from 25th‐29th July 2016 with two archaeologists and the area within the pipeline trench was fully resolved. The pit itself was almost keyhole shaped, with the southeast end being smaller and shallower and forming a step 0.43m deep to access the pit. The northwest end of the pit was much bigger and oval or sub‐circular in shape. Overall the pit measured 5.2m northwest – southeast, 2.4m southwest – northeast and it was excavated to a depth of 1.2m. It was not possible to reach the base of the pit in the centre due to water flowing in from below at a fast rate, but it appeared most likely that the base would not have been any more than another 0.1‐0.2m in depth. The pit was excavated to 3.48m OD. There were five fills contained within the pit. The basal fill, C58 was located in the deepest part of the pit and comprised a loose mid‐grey gritty sandy clay with occasional inclusions of burnt stones and seashells (cockle, whelk, periwinkle), occasional animal bone and moderate charcoal flecks. A sample of alder charcoal from the basal fill was selected for radiocarbon dating and returned a date range of 3797+/‐40 BP, calibrated to BC 2434‐2051 (2 sigma, UBA‐34919) placing this activity in the Early Bronze Age. Above C58, the main fill of the pit comprised moderately compact black silty clay with abundant burnt stones, occasional inclusions of charcoal, seashell (cockle, razor) and animal bone (C57). One flint platform flake was recovered from this fill (16E0101:57:1) (Driscoll, Appendix 5.2). This deposit would have been associated with the heating of stones in a fire for use in heating water in a trough and would have found its way into the waterhole after the feature had gone out of use. It is likely that the water would have been taken from the large waterhole and used in a trough in the immediate vicinity. A localised deposit of compact yellow brown sandy silt was present within the main fill in the southeast of the feature (C60) and represented redeposited natural subsoil. Above C57 a compact mid‐grey silty sand contained occasional charcoal and appeared to be a blending of fill C57 below and the upper fill C56 and it was not noted as a separate context during excavation (C59). The upper fill; C56 comprised a sterile compact yellow brown silty clay and represents post‐use silting of the waterhole. A single flint platform flake was recovered from this deposit (16E0101:56:1) (Driscoll, Appendix 5.2). Of the small quantity of animal bone recovered from this feature, the only identifiable elements were from a calf (Beglane, Appendix 5.7)' (McLoughlin 2019, 317-8)'. See attached photographs and plan of site courtesy of and © Gill McLoughlin of Courtney Deery Heritage Consultancy Ltd. McLoughlin, G. 2019 Final Archaeological Excavation Report, Station Road, Portmarnock, 16E0101. Unpublished archaeological report submitted by Courtney Deery Heritage Consultancy Ltd. to the National Monuments Service on behalf of Sherman Oaks Ltd. Compiled by: Caimin O'Brien based on details provided by Gill McLoughlin of Courtney Deery Heritage Consultancy Ltd. Date of upload: 22 June 2023