Pelagic Foraminifera found in the marginal parts of the limestone at Mount Madai in south-eastern North Borneo indicate that it is of Upper Cretaceous age. Much of the limestone at Mount Madai and Mount Baturong does, however, contain algae and other microfossils characteristic of Lower Cretaceous rocks in other parts of the world.

The limestone is provisionally classified as the Madai–Baturong Limestone Member of the Chert-Spilite Formation. Revision of the stratigraphy has clarified the regional structure, and it is postulated that the Chert-Spilite Formation has been uplifted against Neogene sediments along a major zone of thrust faulting.

Till fabrics on the ridge above Barrington show a variety of preferred orientations and their origins are discussed. Not all the fabrics can be attributed to ice transport. Lowestoft and Gipping Tills are differentiated on their lithologies, fabrics, and erratics, and the contained heavy minerals and microfossils are also considered. Correlation of the associated solifluxion deposits with the sequence in Barrington Village has shown that the Hippopotamus-bearing Barrington Beds are not younger than the Hoxnian Interglacial (Elster/Saale) and may be considerable order.

In the Chambéry region, Jura folds with a north-north-west trend meet the boundary of the Subalpine zone, which strikes north-north-east. The two fold trends were probably not formed at exactly the same time. Minor folding, thrusting on steep planes, wrench-faulting, formation of sub-horizontal stylolites, and opening of filled joints all took place during a succession of tectonic events with maximum compression at about east-west, after the aforementioned fold-trends had been formed. The evidence considered in this study seems incompatible with hypotheses of deformation by gravitational gliding.

Within this area are developed a series of quartz veins which cut three rock types, the Grainsgill granite, part of the southern margin of the Carrock Fell gabbro to the north, and an intervening area of hornfels belonging to the Skiddaw Slate Series. Both the hornfels and the gabbro have suffered thermal metamorphism due to the granite, and in addition, the hornfels has undergone a very localized metamorphism due to the gabbro. All three rock types have undergone a further hydrothermal alteration due to the quartz veins. The microscopic changes involved in this alteration are described and it is shown that the end product in each case is essentially similar to a greisen, with the addition of pyrite and arsenopyrite.

A recent revision of the type Ludlovian succession at Ludlow (Holland et al., 1959) has raised a number of problems concerning the classification and nomenclatureof the proposed divisions. It is here suggested that these can be resolved by adopting adual systemof classification, in which both rock-stratigraphic and biostratigraphic units are recognized. The impropriety of discarding the names Aymestry and Mocktree is established, and a plea is made for the erection of stages to aid in local and regional correlation.

The Cork Red Marble is a coarse, graded but poorly sorted, re-sedimented lime-conglomerate, of Caninian age. It occupies a central position within 4,000 feet of Waulsortian limestones. The pebble content of “porcellanous” calcite mudstone—not in reef facies—is set in a matrix of red clay. Mixed biofacies are represented, because of reworking: fragmented large molluscs, indicative of a nourishing reef habitat, contrast forcibly with a mollusc spat-ostracod assemblage as found in the pebbles. The conglomerate was probably formed when back-reef sediments, which included red clay, were elevated and then redeposited, possibly by turbidity currents

Minor folds in slates and sandstones are upright in the south and northerly overturned towards the north, and plunge approximately E.N.E. and W.S.W. towards three major N.W.–S.E. dextral faults. The folds are monoclinal and angular; regardless of attitude, the short limbs lie on the northerly sides of anticlines. Both slaty and fracture cleavages tend to parallel axial planes and local directions of extension. Similarly, the vertical axial planes may closely parallel those of major folds.

Boudins and W.N.W.–E.S.E. dextral oblique faults indicate extension along fold hinges, N.W.–S.E. dextral cross faults a change to N.–S. compression. Folded basic dykes parallel to faults and joints suggest early initiation of the fractures.

Consideration of the relative rates of uplift-erosion and erosion-denudation leads to the recognition of nine cases which define the conditions of geomorphological evolution. It is concluded that a peneplanated surface may develop during active tectonic uplift, and that the total volume of clastic sediments produced during any stage is inversely proportional to the rate of uplift.

An intrusive sequence of kentallenite-lamprophyre-granite is clearly indicated by cross-cutting relations at Kentallen. This sequence is the same as that recorded elsewhere in Argyll. It is suggested that the time gap between the intrusion of the kentallenite and of the lamprophyre is small compared with that between the intrusion of the lamprophyre and of the granite.

Ocellar hybrid rocks, formed by metasomatic transformation of basalt xenoliths engulfed in granitic magma, are characterized by numerous small, oval quartz porphyroblasts, each sheathed with narrow rims of amphibole. The progressive development of these quartz ocelli, together with the general texture of the ocellar hybrid, is traced through a number of intermediate hybrid types. In some instances, the ocellar hybrid displays an intrusive relationship toward basalt and is thought to have undergone a certain amount of metasomatic mobilization.

The revised classification of the Ludlovian rocks is defended. It is maintained that there is no need for separate rock-stratigraphical and biostratigraphical classifications. The nine new divisions are, therefore, combined units; their number is justified by the detailed mapping and their names are dictated by the requirements of the rocks and not by an arbitrary code of rules. The old classification, using Aymestry Limestone, is considered to be still usable as a crude rock-stratigraphical classification.

Limestones consisting of recrystallized shells of lamellibranchs, originally composed of aragonite, contain a brown-coloured calcite which is strongly pleochroic. Maximum “absorption’ corresponds to the extraordinary ray. The effect is shown to be a pseudo-pleochroism, caused by scattering of the extraordinary ray by inclusions, which follow the shell structure, in the calcite. Aragonite shells, which have not recrystallized, show a pseudo-pleochroism of similar colour but reversed sign. The inclusions originate in the conchiolin of the lamellibranch shell; their present nature is not known. Their progressive destruction by thermal metamorphism is described.

An account is given of the petrography and chemistry of a diopside-orthoclase-hornblende rock within the quartzose garnetkyanite-biotite granulites of the Leverburgh Lewisian paragneiss belt of South Harris.

A soft chalky limestone or coccolith-marl, believed to form a submarine outcrop in the upper part of the continental slope off Brittany, consists largely of coccoliths, with subordinate quantities of foraminifera and sponge-spicules. Of the twenty or more species of Coccolithophoridae found in this deposit, two are preserved as complete coccospheres more frequently than as separate placoliths; these are described and named. The age of the rock is probably late Tertiary.

Evidence is presented which suggests that there is a strong angular unconformity between the Mesozoic sediments and the Tertiary lavas in certain parts of the Island of Mull. The conclusion is drawn that folding movements peripheral to the volcanic centre occurred both before and after the eruption of the main lava succession.

The Mt. Alford ring-complex consists of a central boss of porphyritic microdiorite, granophyre and andesite, with a semicircular zone of rhyolitic and trachytic ring-dykes intrusive into upturned sandstones, and cross-cutting non-arcuate dykes of rhyolite, comendite, trachyte, andesite, phonolite and basalt. The petrology and geochemistry of these rocks are discussed and it is concluded that the various rocks have been produced by differentiation of a basic magma.

The lower Torridonian in its southernmost outcrops is built of felspathic greywacke turbidites, forming a succession probably 2–3 km. thick, overlain by 2 km. of pelitic and semi-pelitic sediments containing thick, current-bedded pebbly arkose horizons, especially near the base. Sedimentary structures in the greywackes include ubiquitous grading, together with flames, load-casts, convolute bedding, and sedimentary injection, brecciation and disruption phenomena. Palaeocurrents in both greywackes and arkoses indicate a southerly derivation. The detrital mineralogy also suggests a common provenance. It is suggested that the greywackes gradually filled their depositional basin and that later sedimentation occurred in a shallow water or fluvial environment.

M'Coy's type material of Hemitrypa hibernica is re-described. The relation between the main fenestelloid structure and the hexagon-mesh superstructure, and the function of the latter, are discussed.

X-ray analyses of selected samples from the argillaceous subdivisions of the English Wealden indicate that illite, kaolinite, and mixed-layer structures are present in variable amounts. The clay mineral assemblage is thought to reflect parent material, weathering conditions in the source area, and possibly some degrading of the illite structure by the action of active waters in the depositional environment. The specific clay minerals are tentatively correlated with the palaeogeographical framework proposed by Allen (1954). It is suggested that the kaolinite was derived mainly from the Palaeozoic uplands, and the bulk of the illite and mixed-layer structures from the marginal Jurassic lowland.

Conjugate shear fold systems are often developed when brittle laminated rocks are subjected to stress. These structures relationship of the principal axes of stress to the surface being folded. Within first order shear zones conjugate second order shear folds may be developed as a result of reorientation of the stress axes in these zones.

The axes of both first and second order conjugate shear folds may form at any angle to the principal stress axes and to the direction of movement within the shear zones. The principal axes of stress are most reliably determined from the orientation of the axial planes of the first order conjugate folds.