Natural pyroxene spinifex-textured rocks, free of olivine, may have MgO contents as high as 15%. If these rocks are allowed to crystallize in the laboratory under equilibrium conditions, olivine is the liquidus phase at 1350°C and pyroxene does not appear until the temperature has fallen to 1180°C. A similar problem is encountered in high MgO komatiites. If spinifex-textured and aphyric komatiites from Munro Township are plotted on an MgO-CaO-Al2O3 diagram, olivine control is evident until the MgO content of the melt falls to 15%. At this point the liquid trend moves away from the CaO-MgO boundary, indicating the crystallization of pyroxene. If a high MgO komatiite is crystallized in the laboratory under equilibrium conditions, pyroxene does not appear until the MgO content of the liquid reaches 9%. It is suggested that experimental and natural systems behave differently because pyroxene has crystallized metastably in the natural system under conditions of extreme supercooling. The early metastable crystallization of pyroxene can only affect the liquid trend if the spinifex zone contains a cumulate component.

New conventional K–Ar dating of virtually unaltered pargasite phenocrysts extracted from a metabasalt of the uppermost Tremadocian Rhobell Volcanic Group, cropping out near Dolgellau, Gwynedd, north Wales, yields an age of 508 ± 11 Ma. This result provides a valuable new time-scale calibration point although incompatible with some other versions of the radiometric time-scale for the Lower Palaeozoic which have indicated ages of less than 508 ± 11 Ma for the Tremadoc/Arenig boundary.

Echinoderm plates from the Protolenus Limestone are recognised as belonging to three groups; plates with folded surfaces, plates with bevelled edges and a third group. They are not comparable with other Lower Cambrian echinoderms and may be derived from a genus or genera of eocrinoid which is not known from complete specimens.

The rarity of calcareous green algae (Order Dasycladales, and family Udoteaceae) in apparently suitable Middle Jurassic facies of southern England is summarized. They are well known from Tethyan areas to the south and opportunities for migration and establishment existed then. It is concluded that tolerance for warm but extra-tropical conditions, which exists in some but not all modern representatives of these algae, has developed gradually since Triassic time and was not well established until Cenozoic time. In Middle Jurassic time few species showed this tolerance, hence the very limited occurrences north of the Tethys.

Palaeochannels developed in a terrace of the River Wey are described. Their morphology, relationship with the underlying Folkestone Sands, and the character of associated superficial deposits all suggest that the channels are examples of thermokarst phenomena, probably of Devensian age.

Stream sediment surveys were carried out on an area of about 200 km2 in the Hamash area. Results indicated that Cu anomalies are concentrated near the intersection of deep-seated tectonic zones and a block fault in the northeastern and southwestern parts of the district. Geophysical techniques, drilling and bedrock sampling show that the Cu mineralization is at the surface, and encrustations of secondary Cu minerals correspond mainly to sulphide-bearing quartz veins and hydrothermally altered granitic and volcanic rocks. No deposits of commercial interest have been found. Under arid conditions reconusissance survey along secondary dispersion trains proved to be a successful method of delineating small zones of Cu mineralization.