1995:090 - DUBLIN: 119–121 Thomas St., Dublin

The site lies outside the walls of Dublin in the medieval western suburb of the city. St Thomas's Abbey, established in 1170, lies to the south-west of the site and much of Thomas St. formed part of the wealthy abbey lands. By 1200 the town of Dublin had spilled out along Thomas St. with references to property plots, houses and shops, including burgage plots, along Thomas St. at this date. A watercourse known as 'Colman's Brook' flowed along either side of Thomas St., entering the city precinct at the north-west corner. The river powered at least four mills along the eastern end of the street, towards the city. A large mill, known as the Blanchardstown Mill, operated on the site as late as 1969.

The site was a large carpark and a total of twenty trenches were opened up, orientated both north-south and east-west. The testing located natural deposits at between 2.8m and 3.5m below present ground level and the area had been partly infilled in the late 17th/early 18th century. The massive limestone walls of the Blanchardstown Mill were also located, as well as a line of red brick walls indicating the presence of houses which originally fronted onto Thomas St.

The watercourse
At the southern end of the site the testing revealed the presence of a possible watercourse orientated east-west, 2.2m below present ground level. The watercourse had an estimated width of 6.5m and was cut into the boulder clay to a depth of approximately 1m. It was filled with grey silt, black gravel and silty organic layers and was inactive. The remains of four timber planks on the southern bank suggest that the watercourse was revetted in timber and was similar in type to the Poddle revetment along Patrick St. The watercourse was associated with medieval clays.

Rath House, Ferndale Rd, Rathmichael, Co. Dublin