1998:652 - MULLINGAR: Blackhall Street, Westmeath

Test-trenching was carried out on various dates in March and April 1998 at the site of the existing Employment Exchange at Blackhall Street, Mullingar. The work was carried out in compliance with a condition within the grant of planning for an extension to the existing building. The extension was to involve the construction of a building in the area of the courtyard at the front of the existing building and the construction of a boiler house and fire escape to the rear of the building.

Testing of the courtyard was by necessity limited to a trench inserted along its east side. A second test-trench was inserted along the open area at the rear of the building. Test-Trench 1 was positioned directly adjacent to the existing eastern site boundary wall. During the excavation of this trench what appeared to be a wall face became visible within the western side of the trench. The top of this wall was revealed at a depth of 1.1m below the surface, while the remaining depth of the visible wall face was c. 0.3m. A considerable amount of disturbance was noticed within the fill surrounding the wall, and the formation level of the wall appeared to rest upon a brown, humic material containing flecks of charcoal, which may represent the original soil cover and which, in turn, rested upon a yellow/beige natural. However, no evidence of the date of the wall was uncovered.

Test-trench 2 was excavated to the rear of the existing building. It was aligned east-west and was 10m long. The stratigraphy in this trench consisted of rubble to a depth of 1.6m over the original topsoil, which had a depth of 0.9m. It appeared in places that the yellow natural was just beginning to appear at the base of the topsoil.

Monitoring was carried out of foundation trenches associated with the extension to the existing Employment Exchange, from 9 to 18 September 1998.

Three main foundation trenches were dug in the courtyard to the front of the existing building. In addition three box trenches were inserted along the east wall of the front part of the building, and some further box trenches were dug on the internal side of its northern wall. Trenches were dug to a depth of 2–2.5m.

Monitoring confirmed the existence of an old soil layer on the site, which consisted of a silty clay. It was organic in texture and contained occasional inclusions of minute fragments of wood, occasional fragments of charcoal and frequent inclusions of animal bone. The absence of modern inclusions within this material was striking, for it was overlain directly by modern rubble. The foundations of the existing building lay upon this layer and had not truncated it. This soil layer extended over the entire area of the courtyard to the front of the existing building and was generally c. 1m deep. It was particularly deep and undisturbed at the southern end and was also found to extend inside the building.

A number of stone walls were encountered in the trench sections. The existence of at least one wall was already indicated during the initial testing of the site. Excavation of a trench along the street front indicated that this wall had not run precisely parallel to the existing site boundary but diverged westwards slightly.

Another wall (No. 2) was encountered in Trench 2. The upper surface of this wall was at a depth of 1m, directly beneath the rubble. This wall ran east-west across the site and could be seen to continue beneath the front part of the existing building. It was also visible in section in Trench 1, and it is probable, on this evidence, that it was functionally related to the wall that ran roughly parallel to the present site boundary. Wall No. 2 was composed of roughly cut and squared blocks of limestone and was 0.9m thick. On its southern side a foundation cut could be seen, indicating that the wall, as observed, represented the foundation courses. These walls may represent relatively late structural walls; several structures are shown on the site on the 1st edition OS map.

At certain places within the trenches layers of a coloured, ashy substance were noticed, varying from light yellow to red. This material appeared to be in some way related to the old soil layer in that it always occurred directly beneath, within or over the soil layer. It was particularly extensive along the street front, where it occurred as a deep layer along the northern face of Trench 3, directly on top of the soil layer. Its presence within and above the old soil layer suggests a domestic origin, and it may represent spreads of ash from domestic fires.

A foundation trench and foundation base were excavated for the structures to the rear of the existing building. Monitoring of these proved that the layer of modern topsoil identified during testing extended to the depth of the natural at 2.5m beneath the existing ground level. There were no intervening layers.

Further monitoring of groundworks associated with this development is to take place in 1999.

39 Kerdiff Park, Monread, Naas, Co. Kildare