Tuesday, August 11, 2009

Road excavation reveals an early medieval mill site in Ireland

A leading archaeologist in Ireland has described the discovery of an early medieval mill site in South Roscommon during excavations on Athlone to Ballinasloe motorway project as "very important".

According to the the Westmeath Independent, the mill site, located in Kilbegley townland in the parish of Moore is estimated to be 1,200 to 1,300 years old. It is one of only a handful of excavated mill sites in Ireland at present and is thought to one of the best kept in Europe.

Jerry O'Sullivan, Archaeologist with the National Roads Authority, said, "It is very important because the parts were very well preserved. After the mill was abandoned it quickly became immersed in peat. This prevented the timbers from being colonised by insects and fungi, and this arrested the normal decay process that would otherwise have destroyed the mill timbers within a few years."

Archaeological investigations commenced along the motorway route back in September 2006, with a phase of test excavations throughout the whole footprint of the scheme, and more detailed investigation of ten new sites that were discovered was completed in August 2007.

Post and wattle mill-races, a millpond, the near complete remains of the lower floor of the mill, also known as the undercroft, a flume, which was used to channel the water on to the water wheel and a large tail race, to allow for the exit of water from the wheel area all survived.

Mr. O'Sullivan said, "They had an excellent understanding of basic engineering that is reflected in their use of the terrain, the natural hydrology, and their skill with timber-built structures. For example, the mill was certainly built by professional millwrights who could cut, shape and join large timbers to create a robust structure, capable of withstanding all the pressures of a dynamic mechanical and hydraulic environment."

He continued: "The main surviving element of the mill is the 'undercroft' or basement level. This had to support the millhouse overhead (this did not survive) and also withstand the pressure of waters passing through it and the rotation of a heavy stone millwheel on its axle.

Big oak timbers were used for this but the millwrights were capable of delicate work too and understood the qualities of different sorts of timber. For instance, yew - which is an especially dense, hard timber, but also rare - was used for a finely worked valve plate that could be adjusted to moderate or stop the flow of water being jetted onto the millwheel."

Located close to the old churchyard in Kilbegley, a couple of miles east of Ballinasloe, the mill probably belonged to a small monastic church, on the hillside south of the new road, and would have been worked by tenants on the monastic estate. Monasteries in early medieval Ireland were supported by their estates, Mr O'Sullivan enthused with lands donated to the Church by its patrons among the local Gaelic tribes. These lands were worked by monastic tenants. Archaeologists and historians believe the grain that was processed at Kilbegly would have come from these estates.

The churchyard in Kilbegly is still in use as a burial ground today but it contains the ruins of a medieval church, and the big, circular earth and stone bank that surrounds it probably dates to the 6th or 7th century. In fact, historically Kilbegly was on a very ancient route way into Connacht, from a crossing place on the Shannon at Snámh dá Éain, meaning Swim two Birds after the two islands in the river there, a placename immortalised in the comic novel by Flann O'Brien.

The NRA hopes to display the remains of the mill site in Kilbegley and artefacts found during excavations along the Athlone to Ballinasloe motorway route to the public some time next year. At present, the mill timbers are being conserved by the York Archaeological Trust in England with a view to bringing them back to Ireland next year for permanent public display.