A thin vein of dolerite at Slemish, Co. Antrim, shows an unusual plane and smooth contact against the dolerite of a Tertiary plug. A columnar growth at the contact indicates special conditions for crystallization. The selvedge is described and an attempt made to explain the growth and orientation of the olivine.

Barth argued that the CIPW conventions governing the calculation of normative pyroxenes and olivines are based upon inadequate or incorrect mineralogical information and should be abandoned. The real occasion for the conventions appears to be petrological, not mineralogical. Qualitative agreement between norms and modes of undersaturated rocks requires the use of these or very similar conventions. Ease of calculation is no longer a major consideration and a more realistic set of rules could now be adopted if it were available.

Large cognate xenoliths showing rhythmic banding in anorthosite and pyroxenite are described from a camptonite dyke. Analyses of the camptonite, a pleochroic titanaugite and a titaniferous brown, hornblende are given.

Eight metabasic bands with pillow structures are exposed in a synclinal area immediately to the north-west of Read's (1955) position for the Boyne Line. Their petrography indicates (a) that they have undergone a sequence of metamorphic changes leading from the production of syntectonic biotite-albite-sphene-iron ore schists, through a stage of static annealing, to the development of post-tectonic amphibolites and (b) that they are of unusual chemical composition. Their stratigraphic position is discussed and compared with that of other occurrences of Dalradian pillow lavas, both in Scotland and in Ireland.

A traverse of a noritic gabbro sill (c. 1,000 feet thick) intruding the Roraima Formation showed no cryptic layering, but small-scale fractionation throughout the sill is indicated by the strongly-zoned plagioclase (An80→40), and orthopyroxene (En79→54) with outer rims of inverted pigeonite. Olivine (Fo80) is only present in the chilled margin.

New evidence on the age of the granites underlying the Roraima Formation is given by the discovery of post-Roraima felsite dykes, with high-quartz phenocrysts.

Five nomenclatural problems in the inarticulate brachiopods are discussed and solutions suggested for them. Two new genera, Eodinobolus, type species Obolellina magnifica Billings, 1872 and Orthisocrania, type species Pseudocrania divaricata M'Coy, 1851 are erected. Clistotrema nom. nov. for Orbicella d'Orbigny, 1847 non Orbicella Dana, 1846 is proposed.

A network texture made of graphite with calcite filling the holes is described from an area of staurolite-garnet grade of metamorphism. It is pointed out that this is the earliest texture preserved in the rock, and that it resembles a cellular structure and may therefore be of organic origin, possibly a primitive plant. At present, however, it is not certain that the structure is organic in origin.

Kaolinite-mudstone bands, widely recoginzed in the Carboniferous of Western Europe, where they are known as tonsteins, are also represented in Britain. On the basis of the probable correlation eight such bands have so far been found in the Coal Measures of the East Midlands. Laterally two of these bands are thought to pass into rocks intermediate in type between tonstein and more normal Coal Measures mudstones.

Complex fold patterns are described from a strongly deformed marble group in Northern Norway. The patterns are analysed in terms of fold superposition. One set of folds presents difficulties to such an explanation and an alternative possibility is discussed.

Intensive structural and stratigraphic studies, supplemented by nine new absolute age data, have led to the recognition of two distinct orogenic belts in the Pre-Cambrian tract of Singhbhum and adjacent areas in India. The Iron Ore orogeny in the south, characterized by the generally low grade metamorphic, N.N.E.–S.S.W. trending formations, had its culmination in the emplacement of the batholithic body of Singhbhum granite (c. 2,000 m.y.). These rocks are separated by a prominent thrust zone (Copper Belt thrust) from the E.–W. striking, generally high-grade meta-morphic rocks of the Singhbhum orogeny whose closing age is 905 to 934 m.y.