Before referring to the Boulder-clay of Scotland it will be well to consider similar deposits on the other side of the channel in the north-eastern portion of Ireland, where they have for many years been the object of careful investigation by local geologists. Boulder-clay as it occurs in Ireland may be described as a hard tough compact clay in which boulders, large and small, and clay, are mixed together in a confused unstratified mass. The boulders and stones usually have their angles more or less worn off, the surfaces being frequently smoothed and marked with grooves and striae. By far the greater portion of the stones are of local origin, but a considerable number have been transported from a distance. The underlying rocks on which the Boulder-clay rests are invariably eroded, and bear striae which tell of ice moving over them from the north, north-east, or more rarely north-west, the stones in the clay also indicating a similar movement, their origin being almost invariably from sources further north. This clay forms the subsoil of most of the district referred to, as also that of the greater portion of the British Isles. It is found covering both the hillsides and the valleys, but is best seen along the margins of the glens where the rivers and the streams have cut through it, exposing sections, or where artificial cuttings have been made in quarries, railways, borings, and other works. The excavations made some fifty years ago for the Belfast Water-works gave the This 250-word extract was created in the absence of an abstract