1995:126 - PORTUMNA CASTLE, Portumna, Galway

A preliminary archaeological excavation was carried out at Portumna Castle in April-June 1995. The castle, which was completed in 1618, is being restored by the National Monuments Section of the Office of Public Works. Preliminary investigations were carried out in the castle basement in order to assess flooring levels and to identify problems with the internal stone-lined drain which had not been working satisfactorily, resulting in flooding of the basement. The drive leading from the outer gate to the courtyard gate was also fully excavated. It measured 147.5m in length and 4 to 4.6m in width and would appear to be quite late, probably dating from around the end of the 18th century. This would fit in well with the dates for the Adam gate which stands at the north end of the drive (the outside gate), and the outer courtyard gatehouse which stands at the south end of the drive. The drive consisted of a compacted hard core base and thin overlying layer of gravel. It has a maximum thickness of 0.12m and lies directly on the natural boulder clay. The driveway, though carefully constructed, does not appear to be impressive and may have been used only for a short period of time. Nevertheless it was in use long enough for traces of wheeled vehicles to be left in it. Along the centre of the drive three tracks were visible, running in a north-south direction. These were barely visible when first exposed and measured 0.20 to 0.25m in width and 50mm deep. The three tracks appeared to be cut into the top gravel layer and represent the use of horse-drawn vehicles over a period of time.

With regard to the interior of the castle, quite a large amount of material has been removed over the years since the castle was gutted in a fire in 1826. No evidence of this fire was retrieved during the excavation and so we must assume that the castle basement was cleared out right down to and even beyond the 1826 floor level. Only a small portion of a flagstone floor survives in the south-west corner of the castle. Elsewhere mortar floors survive, which seem to be sitting directly on the boulder clay.

Various other features also survive which warrant further attention. These include evidence of internal partition walls, the foundations of which are composed of brick. Apart from the rock-cut well in the south-east corner of the castle, the stone drain is the principal feature in the basement and is an important and integral part of the castle itself. The drain extends diagonally across the castle from the north-east corner to the south-west corner and continues on outside the castle. It is constructed principally of stone with mortared sides and a stone floor. The roof was lintelled with large stones and the drain maintains a constant width and depth of about 0.45 to 0.5m. Levels taken on the floor of the drain indicate a fall from the north-east corner towards the south-west corner of 0.2m. There is a vertical chute built into the castle walls in both corners which led straight into the drain, presumably from garderobes on the first floor. The ultimate origin and destination of the drain remains unclear but its function was varied.

Several other drains were also constructed which led into this main drain. One stone and brick example starts in the south-east turret and continues up the middle of the kitchen floor before reaching the main drain near the west end of the kitchen. A second drain, constructed entirely of red brick which also empties into the main drain, was discovered during the present excavation in the north end of the castle and would appear to originate somewhere in the north-west corner. Outside the south-west corner of the castle, stone drains from the downpipes also lead into the main drain, which continues out underneath the original bawn wall and the later ha-ha. There is a marked difference between internal and external ground levels, which results in water flooding into the castle basement. The stone-lined drain is entirely silted up and it is intended that this drain will be fully excavated in 1995, together with the entire castle basement.