Data is presented on textural variation, optical properties, and resultant compositions of the olivines from a differentiated teschenite sill. The range in olivine composition is from Fa21 to Fa,60. Both the individual crystals and successive crops of crystals become more fayalitic with progressive differentiation.

At two localities near Kanye, in the south-eastern Bechuanaland Protectorate, formations previously assigned to the Waterberg System are now correlated with the Pretoria Series of the Transvaal System. In addition to modifying the palæogeography of the Transvaal period, this correlation may also help to clarify the stratigraphical position of the Matsap Series of the Cape Province.

A preliminary analysis of slope forms in Buganda has indicated an erosional cycle characterized by both parallel scarp retreat and summit lowering, of which the latter process predominates in the later stages of the cycle. The recognition of characteristic stages in the erosional development of the landscape may provide a means of distinguishing a warped erosion surface occurring at differing altitudes from the products of separate erosion cycles.

The field relationships between the Armorican granite of North-West Jersey and the Precambrian sediments in the Le Pulec and L'Etacq areas are described together with the petrography of the contact rocks. Trace-element determinations on rocks from two traverses across contacts in the area, and upon control specimens of granite and sediments supplement the petrography. The mechanism of granite emplacement in this area is discussed.

A series of terraces in the Dale Valley south of Dalsfjord has been mapped, and heights have been established. The results have been analysed into a sequence of stages, and compared with general conclusions advanced by J. Rekstad and F. Nansen, on the isostatic displacement of postglacial terraces in Norway.

For certain unconsolidated sediments there is a linear relationship between the arithmetic mean size and the “grading factor”, and sediments with an average particle size of 0·2 mm. show the maximum degree of sorting. An hypothesis has been developed to explain this relationship in terms of the environment of deposition.

Li, Rb, and Cs were determined spectrographically in twenty-eight trilobites, two xiphosurida, four insects, four Crustacea, and six brachiopods. The sediments associated with fifteen trilobites were also analysed. Compared with igneous and sedimentary rocks, the trilobites were characteristically enriched in cesium relative to rubidium and potassium. Thus, the K\Rb ratios were normal, but the Rb\Cs ratios were anomalously low. The evidence is considered to favour the view that cesium has been preferentially concentrated by trilobites during growth. The matrices had Rb\Cs ratios similar to normal sedimentary rocks.