Re-examination of the nephelinites of Etinde, Cameroons, carrying a composite structured “nepheline” mineral shows that the feldspathoid is a genuine nepheline, in part exhibiting twinned intergrowths, and not a potassic orthorhombic feldspathoid phase. Analysis indicates a composition with a mol. ratio of 3·6. Comparison is made with other nephelines in contrasted host environments.

Limestone inclusions in granite show a skarn armour made up of definite mineral zones. From the limestone side these are in order: grossular zone (with or without idocrase), clinozoisite zone, plagio-clase-pyroxene zone, and finally a hornblendic or dioritic zone that passes into the biotite-granite or granodiorite of the district. These different zones were not static but moved into the limestone, each zone replacing the one preceding it and being replaced by the zone following it. A mechanism by which limestone inclusions disappear in granite is clearly exemplified.

The picrite of the Garbh Eilean–Eilean an Tighe sill occurs at a number of points not previously recorded. Its junction with the overlying picrodolerite is not gradational and it does not maintain a uniform level in the sill.

Optical methods are employed in the re-determination of the composition of the olivines throughout the Garbh Eilean Sill. The olivines in the upper picrodolerite and the crinanite are zoned. The range of zoning and the iron content of the olivines increase progressively with height in the sill.

A preliminary examination of Moine rocks containing rolled garnets from three widely spaced localities in the North-West Highlands indicates that the lineation in all cases is parallel to b. This is in accord with Phillips' theory that the metamorphism of the Moine schists was due to movement in a north-easterly or south-westerly direction. A Caledonian age for the metamorphism of the Moines therefore appears to be unlikely.

Moraines which in one case at least contain striated boulders, show that, at the maximum of Quaternary glaciation, small, thin glaciers developed in the island of St. Kilda at certain favourable places. There is no evidence that the Hebridean ice sheet reached the island and no signs of raised beaches which would indicate recent emergence.

The development of potash-rich pyroxene-bearing rocks around inclusions derived from the Appin limestone is associated with the transfer of magmatic silicon, aluminium, iron, and sodium. Calcium lost to the magma, by combining with further silicon, aluminium, and sodium to form a marginal zone rich in plagioclase, has left the magma enriched in potassium.

Daviesiella destinezi (Vaughan), a large concavo-convex brachiopod, is very common in some of the Lower Carboniferous limestones of North-West Ireland. It appears to be confined to the C2S1 subzone. Easily recognizable in the field, it is thus a useful index fossil of the subzone. As the previous descriptions of the species are far from complete, a detailed description of some unusually well-preserved specimens from Co. Fermanagh is given and an attempt is made to relate certain features of the morphology of the specimens to their environment.

The occurrence, very rare in Karroo rocks, of a gastropod species in the Lower Beaufort stage (Upper Permian) of Southern Rhodesia is recorded. It is a small form apparently related to species found in the Tartarian stage of the Russian Permian. These species have been described under extinct marine genera, but on account of their morphology and non-marine habitat this is thought to be inappropriate. The new species much resembles some representatives of the modern genus Hydrobia, not previously recognized in pre-Mesozoic rocks, and it has been decided to describe it as a new species, Hydrobia gondwanica.

During a study of a Carboniferous blastoid fauna from Grassington, Yorkshire, over a thousand blastoids were collected, of which 45 individuals were referred to the genus Codaster. This study has left no doubt that the two species Codaster acutus McCoy and Codaster trilobatus McCoy are synonymous. Codaster trilobatus (in the sense of McCoy's original description), is an old age form, its characteristic feature only being attained by a minority of long-lived individuals. Codaster acutus McCoy is the valid name, being the first described, and is also the type-species for the genus. In order to supplement observation on these specimens, biometrical methods have been employed to study the relative growth of the height, diameter, and number of hydrospires.