in Firhouse, and carried by the three-kilometre first section of the City Watercourse. The ancient artificial watercourse was made by monks not later than the 1240s, and its use later extended with the sanction of the Anglo-Norman administration in Ireland. The watercourse takes an interesting bend after it crosses under Wellington Lane, which looks like the reuse of an existing ditch around an earlier ecclesiastical site. Often roads follow the boundaries of such sites, and this would be a rare example of a watercourse doing so. Near the northern end of the artificial connection was a major milling complex, the Mount Down Mill. Kimmage, Crumlin and The Tongue The point in Kimmage where the City Watercourse joined the river is known exclusively as the Poddle. It continues on through the district, tending northeast, and passing through the Kimmage Manor complex, where it actually goes under one of the buildings. The river's main course through the manor complex is supplemented by a culverted channel along its edge; the flow goes through the surface channel only in normal conditions but when it rises in spate, it overflows into the culvert too. At the end of the grounds, the flows combine and exit in a culvert for some hundreds of metres. The Poddle passes the K.C.R. (Kimmage Crossroads), and Poddle Park and Ravensdale Park, once the site of another mill complex and now a small public park. After a mix of culverted and open sections, it reaches Sundrive Road in Crumlin, where a shopping centre was built on the site of another former mill, the Larkfield complex. The river's line divided at the site of an ancient structure called "The Tongue", near what is now Mount Argus monastery in Harold's Cross. This is a wedge of stone, also known as the "Stone Boat", that divides the flow, in a 2:1 proportion when a certain depth of flow is reached. While the current "Stone Boat" is a modern replacement, it was formed based on the preceding structure (constructed in 1245), which lay in an open area called the Tongue-field; it is now on a suburban street. The restoration or rebuilding was done by the company, Tiernan Builders, who built the modern housing adjacent. The lesser portion formed the second section of the man-made City Watercourse, heading north for Crumlin Road and Dolphin's Barn. Its line passes the Grand Canal east of Dolphin's Barn Bridge,