Four species of Exoconularia, including E. istanbulensis, sp. nov., and one Archaeoconularia, are recorded from beds hitherto regarded as Silurian, but which are now shown to be of Middle Ordovician age. A revised stratigraphical succession is proposed.

Details of the Infra-Cambrian Polarisbreen Series are given, arising partly out of observations made since they were defined in outline by the authors in 1956. The Polarisbreen Series includes the distinctive Polarisbreen Tillite Formation, which correlated with the neighbouring Sveanor Formation of Nordaustlandet and with other tillites in Vestspitsbergen. They are regarded as a product of the great infra-Cambrian ice age and are correlated with world-wide tillite horizons of this age.

The crystallographic orientation of optic axes, the crystallographic orientation of {0112} twins and the dimensional orientation of calcite from a drag folded vein are described. The external movements that have caused the deformation of the vein are interpreted and the fabric characteristics are related to them. The calcite fabric shows a marked similarity to those which have been produced experimentally. An analysis of the quartz fabrics demonstrates that there is no significant preferred orientation of optic axes.

The deformation produced by the pre-Upper Old Red Sandstone movements on the Highland Boundary Fault in a zone close to the fault was sufficiently intense to rupture the pebbles in conglomerates. The patterns of pebble fracturing are similar in type and orientation over a wide area and are comparable with the patterns obtained in the experimental deformation of brittle materials. In experimental deformation a direct relationship has been established between the fractures and the causal stresses and so from a statistical orientation of the fractures in the pebbles the directions of the principal stresses can be deduced.

The principal compression in the vicinity of the Highland Boundary Fault acted N.W.–S.E. varying in places to N.N.W.–S.S.E., normal to the trend of the fault, while the least principal stress acted parallel to the strike of the fault.

The orientation of the least principal stress parallel to the direction of the fault in the conglomerates arises through increased stress in a vertical direction due to the nature of the downbuckling of the rocks on the southern side of the fault.

The orientation of the maximum compression confirms the Highland Boundary Fault as a reverse fault of late Caledonian age rather than a Proto-Armorican wrench fault produced by N.N.E.-S.S.W. compression.

A report is given of the origin, aims, proceedings, and conclusions of the “Colloquium on the Jurassic” held in Luxembourg, August, 1962. The English version of its recommendations to the International Geological Congress are quoted in full; the effects of their adoption on current English usage are discussed and some critical opinions on the report of the International Sub-Commission on Stratigraphical Terminology are expressed.

A detailed examination of some new exposures in the Ben Lawers range reveals folds of three deformational episodes. These are described megascopically and microscopically. The foldgeometry is complex but the kinematic axes of each deformation are shown to be closely related. The folds of the first deformation have relationships which confirm the position of these rocks on the inverted limb of the Tay Nappe. Folds with relationships shown by those of the second deformation have not been described from adjacent areas. The folds of the third deformation are associated with the formation of the Ben Lawers Synform

Fluting (magmatic rolls ?) resembling flow-cast structures in sediments is recorded from certain Kenya lava flows. It is attributed to flowage of underlying moist sediments under the weight of the overriding lava flow.

The Marumbe complex is a small ring-intrusion consisting essentially of a plug of nordmarkite separated from the basalt country rocks by a later ring-dyke and roof-sheet of granite. The lower and upper surfaces of a screen of basalt, which lies between the top of the nordmarkite body and the base of the granite roof-sheet, correspond to successive horizontal fractures which permitted blocks limited by ring-fractures to subside as the nordmarkite and granite magmas were intruded. A series of sheets of granite are developed locally in the hanging-wall of the above-mentioned ring-dyke, and further granite ring-dykes cut the nordmarkite and the country rocks.