Fossils collected during the past sixty years from the uppermost division of the approximately 2,000 ft. thick Llanberis Slates have been re-examined. All but one fossil came from the famous Penrhyn Quarries at Bethesda, Caernarvonshire. The fauna is described as containing Pseudatops viola (H. Woodward), Eodiscus sp., cf. Protolenus howleyi (Walcott), Hyolithes cf. hathewayi G. F. Matthew, H. sp., and a fragmentary crustacean. The last offers no evidence of age but the remainder are considered to indicate a high Lower Cambrian horizon. Illustrations of some of these fossils are given for the first time. The Hyolithes is interpreted as carrying a pair of fin-like skeletal outgrowths and the morphological significance of these is discussed in a statement which comments on the obscure systematic position of the Hyolithidae.

It is claimed that the Bathonian gastropods recently assigned to Bathonella Yen do appear to not differ from Viviparus in any marked features of generic importance, and that there is really no satisfactory evidence to show that they and certain associated organisms lived in the sea rather than in fresh or brackish water.

The mechanism of the compaction of sediments is discussed, with special reference to the rôle played by adsorbed water, under both normal conditions and conditions of erosion and tectonic force. The effect of adsorbed water on the migration of oil and gas, and the possible relation of sediment-compaction to submarine slumping and sedimentary volcanism are also reviewed.

Quartz sand, sodium aluminate and water were heated together in a bomb to above the critical temperature. The apparatus was designed to give a temperature difference of about 100°C. between the two ends of the bomb. Quartz, albite, and analcite were formed in the low temperature end of the bomb.

An example is described of a dyke feeding a lava flow in the Tertiary basalt plateau of North-East Ireland. The dyke has an erratic course and branches into several veinlets, but otherwise it displays the usual characters of a dyke. Continuity between dyke and flow is seen in five places in the restricted area of outcrop of the flow. The possible relationship of the dykes and volcanic plugs of Antrim to the plateau lavas is briefly discussed.

The vertebrate fauna from the Bugti Bone Beds was at first assigned an Upper Nari age by Pilgrim. Later, he assigned them to the Gaj, on the basis of the identification of three species of Ostrea by Vredenburg. Regional field work carried out by members of the geological staff of the Burmah Oil Co., Ltd., showed that the beds really belonged to the Upper Nari after all. Re-examination shows that the identifications of the oysters cannot be upheld, and that there is no palaeontological evidence against the beds being of Upper Nari (Basal Miocene) age. It is therefore necessary to regard the vertebrate fauna as being of Upper Nari (Basal Miocene) age. A list of the species is given for purposes of reference.

A description of the Ingletonian Series is given, with special reference to the sedimentary structures which occur and their use in determining the nature of the folding of the beds; this is shown to be isoclinal. The age of the series is discussed, and it is considered to be in all probability Pre-Cambrian.