Recent studies of the effects of folding on the orientation of primary sedimentary lineations have been restricted to cylindrical folds. This work is now extended to include conical folds.

Bedding mullions have been produced by compression parallel to bedding in the hinge region of a large recumbent fold. Geometrically, the mullions are a combination of parasitic folding, with characteristic gadrooned profile, and cleavage planes. The cleavage is not an axial plane structure, but where fully developed produces a perfect slate fabric in rocks of appropriate lithology. The mullions are found on both sides of a bed of inferior slate sandwiched between two beds of good roofing slate. Boudinage structure results where the mullions are exactly back to back, and the planes of separation provided by the cleavage are infilled with coarse calcite. The slates are interbedded and interlaminated with limestone.

Such boudins are unusual in that they occupy the hinge region of a fold and result from compression parallel, rather than at right angles, to the bedding.

At Uloa in Zululand a nodule bed is the basal formation of a thin group of Tertiary sediments that rests on nearly horizontal Senonian silty mudstones. It contains mammillary, botryoidal, and cylindrical nodules, remanié Lower and Upper Cretaceous mollusca all ferruginized and partly pyritized, silicified Cretaceous wood, worn Tertiary sharks' teeth, and cetacean bone, phosphatized nodules of both Upper Cretaceous and Victoriella-bearing Eocene, and Tertiary glauconitic sandstone pebbles dated at 55 million years.

A coquina-like limestone (“Pecten Bed”) overlies the irregular upper surface of the nodule bed disconformably. Consideration of some of the megafossils, the absence of larger Foraminifera, and the presence of Orbulina universa suggest that the “Pecten Bed” is Middle to Upper Miocene in age.

Alternations of coarse and fine grained calcarenite layers that overlie the “Pecten Bed” disconformably, may be of youngest Miocene age.

The nature of the Tertiary rocks suggests shallow water sedimentation from the Eocene to latest Miocene, with several periods of transgression and regression, and slight epeirogenic or eustatic movement only.

Investigations of the sedimentary rocks of the Umkondo System have enabled six zones of eastwardly increasing metamorphic grade to be delineated on the basis of index mineral assemblages in pelite horizons.

Chlorite, garnet (almandine), staurolite, kyanite, and sillimanite isograds have been recognized over a distance of 500 km. along the eastern border of Southern Rhodesia and are plotted on a map. More detailed reconnaissance work has been confined to the Barué highlands north-east of Inyanga. In addition, a “zone of intermediate isotopic age measurements” is proposed to the west of the lowermost chlorite zone. The isograds lie parallel to the structural edge of the north-south trending Mozambique orogenic belt and can be joined with those of similar metamorphic rocks in the east-west trending Zambesi orogenic belt, suggesting contemporaneity of the c. 500 m.y. regional tectono-thermal event in these two belts.

Certain lamprophyres in Moidart exhibit at least three sets of minor structures (cleavages, lineations and small-scale folds). During the formation of the first set the lamprophyres acquired a schistose fabric: hornblende and biotite laths crystallized along the axial surfaces of tightly compressed folds. The deformation episodes recognized in the lamprophyre sheets post-date the main episodes of major and minor folding (F1-F3) that affected the surrounding Moine gneisses. The existence of a metamorphic fabric in these lamprophyres raises interesting problems—was the thermal energy required to “metamorphose” the lamprophyres derived from deformational heat, or by a heat flow from the Moine country rocks, or were the lamprophyres deformed during cooling and consolidation from the magmatic state (autothermal metamorphism) ?

Various limestones of Middle Jurassic and younger age in the Middle East and Britain, and certain Recent calcareous marine sediments contain pellety debris stained grey or black with finely divided pyrite. The staining appears to involve deposition on pellety debris of limonite, followed by its reaction with bacterially produced hydrogen sulphide to form first ferrous sulphide and subsequently pyrite.

The Lower Cretaceous Palaeogeography of the British Isles and surrounding areas is postulated from micropalaeontological and stratigraphical evidence and its implications discussed.

Specimens of Parabrograptus and Sinograptus from western Canada are described for the first time. An amended diagnosis of Parabrograptus is given. One pyritized fragment of a sinograptid stipe exhibits characters intermediate between Holmograptus and Sinograptus.

The model recently proposed by Kemežys for the distribution of punctae on the brachiopod shell is examined and found to be insufficient. An alternative model is proposed: punctae appear to conform to a hexagonal close-packing pattern on the shell surface. A hypothesis to account for this is introduced, and further implications are discussed.

Joints (fractures) are propagated from areas of high to areas of low stress. They may originate at inhomogeneities on, or by slickensiding along bedding planes. Plumose marks on the surfaces of joints radiating from volcanic, meteor, or man-made explosion craters should, in stratified rock, reveal whether the joints were propagated with their leading edge convex or concave forward.