2025:506 - N18 Plaza, Kilbreckan, Ennis, Clare

Service Station Area

The site was rough pastureland. Topsoil consisted of almost black, peaty soils a maximum of 0.3m deep. The exposed soils beneath were composed of stone, mixed soils and construction waste materials. Natural bedrock was encountered at the raised area of the field in the northeast.

Test pits were dug within the footprint of the foundations of the proposed buildings and in the locations of fuel storage tanks for the proposed service station area. These were excavated through mixed stoney deposits that included construction debris and mixed soils, to a depth of 1.6–1.8m and reached bedrock at a common level across the site.

Ground Investigation Works

A licence amendment to include monitoring of ground investigation works was submitted and approved by the National Monuments Service in April 2025. Archaeological monitoring of site investigations including test pits and slit trenches took place on an intermittent basis between May and October 2025. These investigations were located adjacent and to the north of the current N85 road and were between 300m and 500m from Clare Abbey (CL033-120—-). The majority of the pits and slit trenches showed evidence of previous disturbance from the construction of the adjacent N85, or, in the case of pits 3 and 4, from the flood defence works along the riverbank. Where no evidence of previous disturbance was noted the stratigraphic layers were sterile and natural. The pits measured approx. 2m x 1.5m and were dug to a depth of approx. 2m. The slit trenches varied in length (up to 50m) and measured 1.2-2m wide and were excavated to a depth of 0.8-1.2m.

• Pit 1 – this was located in a field used for grazing. A deposit of limestones, likely construction debris from the nearby N85 was noted in the top of this pit to a depth of c. 0.4 m. No archaeological deposits were noted.
• Pit 2 – this pit was located adjacent to the railway line. The deposits here were slightly peaty in nature. No archaeological deposits were noted.
• Pit 3 – this pit was located in the vicinity of the flood defence works and nature reserve area on the banks of the River Fergus. Stone deposits from the construction of either the N85, or these flood defences were noted. Deposits were peaty and showed waterlogging. No archaeological deposits were noted.
• Pit 4 – this pit was located in the vicinity of the flood defence works and nature reserve area on the banks of the River Fergus. Stone deposits from the construction of either the N85, or these flood defences were noted. No archaeological deposits were noted.
• Pit 5 – this pit was located on the verge of the local road which provides access to Clare Abbey. No archaeological deposits were noted.
• Pit 6 – this pit was located on the verge of the local road which provides access to Clare Abbey. No archaeological deposits were noted.

Slit Trenches

A series of slit trenches (1-4) up to 50m long were excavated along the northern side of the current N85 road within the scheme boundary area under archaeological supervision as part of the ground investigation works during September and October 2025. In September two slit trench excavations were monitored. Slit trench 1 was located directly to the west of the Skehanagh roundabout measured 40m long, 1.2m wide and was excavated to a depth of 0.8m. The upper stratigraphy from the surface to 0.4m depth comprised a natural sterile peat layer which overlay a light grey natural marl recorded at 0.4-0.8m depth. Natural limestone  bedrock was also observed in places at this depth. No archaeological deposits were noted within this slit trench.

Slit trench 2 was located to the west of the L4116 junction on the northern side of the N85 and measured 50m long, 2 mwide and was excavated to a depth of 0.8m. The stratigraphy comprised of made ground with mixed soil, rock and geotextile, most likely related to the construction of the N85. No archaeological deposits were noted within this slit trench.

Two additional slit trench excavations were monitored in October. The first, Slit trench 3, was located directly west of the M18 Plaza along the northern side of the N85. It measured 40m long, 2 mwide and 1.2m deep.  The upper stratigraphy comprised grass and sod to a depth of 0.4m over a layer of 804 gravel to a depth of 1.2m. No archaeological deposits were noted within this slit trench.

Slit trench 4 excavated in October was located directly east of the Clare Abbey roundabout along the northern side of the N85. It was 40m long, 1.2m wide and 1m deep. The stratigraphy comprised a disturbed/made ground layer to a depth of 1m. No archaeological deposits were noted within this slit trench.

Monitoring of topsoil stripping at the site of the proposed services station at Kilbreckan revealed no undisturbed original or natural deposits. Natural bedrock was encountered at a common levels across the site at depths of 1.6-1.8m. The excavation of test pits and slit trenches as part of related site investigation works adjacent to the N85 road showed only mixed and natural deposits which included stone and construction waste materials as well as marls.

Previous archaeological test trenching at the site in 2015 revealed no archaeological remains (Hession, 2015) and other contractors at the site have reported that the area was heavily disturbed and quarried for stone during the construction of the adjacent M18 Motorway.

References

Hession, J  2015  Report on Archaeological Test Trenching for a proposed motorway service area and rest area adjacent to Junction 12 of the M18 located at Kilbreckan, Doora, Ennis, Co. Clare. Excavation License 15E0291. Unpublished archaeological report.