(1) Boulder Clay from Craig, west of Llaudulas, to the Vale of Clwyd, south-east of Abergele. Immediately east of Craig, between Llandulas and Colwyn Bay (No. 1 in the Map) the Boulder Clay stands out in vertical cliffs about 30 feet high, and so compact that it is undercut by the waves, in a manner similar to that often seen in rock-cliffs. A closer examination shows that it is very full of angular fragments of limestone, derived from the Carboniferous Limestone-rock against which it lies. Several large blocks of Welsh felstone and blocks of slate-rock—showing banding or original bedding—occur on the shore, and I found a small boulder of Eskdale granite in the clay. At one place the clay appears to be foliated in a vertical direction. It does not appear that there are many shell-fragments in the clay, as I found only one example. All the Boulder Clay described in this paper is of a brown or reddish-brown colour, containing northern erratics, and is similar to the low-level Boulder Clays of Lancashire and Cheshire, excepting where it is mixed with the waste of the hills against which it may happen to lie. A microscopic examination of a specimen of the clay by Mr. Joseph Wright, F.G.S., for foraminifera yielded negative results. The following is a mechanical analysis showing the coust, itution of the clay ; specimen taken about 5 feet above the shore :— This leaves 50 per cent. of clay, if we count as clay all the material