The Ards peninsula, which forms the eastern part of Co. Down, is about 20 miles long and varies from 3 to 5 miles in breadth. On the west it is separated from the mainland by Strangford Lough, the east coast facing the Irish Sea.

The Cardiganshire coast shows various geological features of considerable interest. The present paper deals chiefly with the character and evolution of the coastal slopes and cliffs in the north of the county, between Borth and Aberayron.

The following is a tabular summary of the rocks of north-eastern Antrim.

Among the recent additions to the collections of the Geological Department of the British Museum are two small consignments of fragmentary bones and teeth from the Directors of the Geological Surveys of Nyasaland and Tanganyika Territory. They are badly weathered, but, even though generic identification is alone possible, remains of fossil mammals from these areas reach Europe so seldom that the genera represented are worth placing on record.

Methods and apparatus used in the isolation of heavy minerals vary considerably with different workers and this lack of uniformity obviously reduces the value of the conclusions in a branch of petrology in which quantitative data are essential. Panning in water and separation in bromoform are probably the two methods most widely adopted; but even with these there is considerable variation in the apparatus, each investigator using his own special panning device or type of separator. Also, whereas some writers employ direct bromoform separations, others treat the sediment by preliminary panning, and still others are content with panning alone. A paper published recently by Dr. F. Smithson showed the effects of panning on a crushed sandstone from the Yorkshire Trias and the results were compared with those of direct bromoform separations. The divergence of results was so great that it seemed worth while to carry out a similar type of investigation on some normal unconsolidated sands in which the heavy residue makes up about 0·2 to 0·3 per cent of the total bulk. The samples used in this case were mostly from the northern outcrop of the Folkestone Sand in the Weald, but some samples of Eocene Sands from the Continent were also examined.