Having on several occasions described the rocks of Moffatdale to the Society, I shall confine my remarks to-night to a few minor details connected with them, aided by a number of hand specimens I have brought for illustration. It may safely be asserted that few other stratified rock formations have undergone such an upheaving, crushing, and contorting, as the Silurian, for its strata are to be found tilted from their original level at all angles—up to the perpendicular, and even inverted. Occasionally the folds take many strange and fantastic forms, as is more particularly the case with the black mud-stones or graptolitic shales. The prevailing rock of the district round Moffat is Silurian grit or grauwacke, the whole of the hills being chiefly composed of it, and its accompanying thin flaggy grits and graptolitic shales, which crop out frequently at certain points along the valleys. These rocks also stretch right across the country, from an anticlinal axis at Birkhill to the Irish Sea on the one shore, and to the German Ocean on the other. The hills built up of these rocks are all verdure-clad to their summits, except where they are scored and cut into by the mountain streams. The grauwacke is largely used in the neighbourhood for building. I exhibit a specimen from Wellhill quarry, which is said to be the best in the district for such purposes. It is crystalline in texture, and is of a fine grey colour, but varies according to locality, being sometimes of This 250-word extract was created in the absence of an abstract