Magmatic differentiation is demonstrated in two epidiorite sills from the Grampian Highlands of Scotland, and the distribution of major and minor elements compared with data given for other intrusions, and for trace elements in the Whin Sill at High Cup Gill, Westmorland. The latter sill has Sr and Ba enriched towards the top. The element distribution for the epidiorite sills indicates that they are overturned. The data are conclusive for one sill but merely suggestive for the other, since such phenomena as multiple injection may also have affected the element distribution. The structural significance is briefly discussed.

New potassium-argon age determinations are presented for rocks ranging in age from Lewisian to Tertiary. A late-Caledonian metamorphic event at about 422 million years is very important in the Highlands and the relationship of this to previous metamorphisms is discussed. Newer Granite emplacement took place about 400 million years ago and the Moine thrust movement also took place at about this date. Lower Carboniferous basalts yield, by whole rock methods, ages compatible with the time scales of Kulp (1960) and Holmes (1959). Volcanic activity in Mull is confirmed as Palaeocene or Eocene in age.

A fenestrate bryozoan species recently collected from the Visean of County Fermanagh, Ireland, appears to correspond in all respects with Retepora nodulosa Phillips, from a similar horizon in Yorkshire. The last-named form was never satisfactorily defined or illustrated, the original type material is lost, and after being neglected for many years the name was declared a nomen dumium by Miller (1961). It is now recognized that, because of the presence of biserial carinal nodes, the species properly belongs in the genus Minilya, Crockford, 1944. It is here redescribed on the basis of a neotype from Fermanagh.

Axial-trace-fractures are defined as joint or fracture cleavage surfaces which intersect bedding surfaces parallel to adjacent fold axes, and which meet stratigraphically higher bedding surfaces at acute angles closing towards adjacent anticlinal hinges. In the Upper Palaeozoic rocks of South Pembrokeshire these fractures are developed equally on fold limbs, in regions of low dip, and around fold hinges. Characteristically they are interrupted at bedding surfaces and vary in frequency with lithology. The value of the angle they subtend with bedding surfaces varies with lithology and dip.

Calcareous concretionary rods, thought to have been originally normal to depositional surfaces, are now orientated parallel to axial-trace-fractures and at right angles to fold axes.

The axial-trace-fractures of South Pembrokeshire are considered to have been formed immediately before or at the start of the Armorican folding, and then to have been rotated and sheared during the folding.

Other joints associated with axial-trace-fractures are described and briefly discussed.

A structural analysis of the cliffs and one pit section in Pleistocene deposits at Weybourne has shown one major phase of ice movement only. Ice moving from approximately 210 degrees caused the disturbance of the upper part of the Chalk (together with the overlying Weybourne Crag) and the deformation and deposition of a chalky-boulder-clay, thought to be equivalent to the Lowestoft till.