Thin coccolith-rich bands, in which coccoliths make up a major part of the rock, have been recorded at 11 horizons in the Kimmeridge Clay of Yorkshire, Lincolnshire, Norfolk, Surrey and Wiltshire and also in cliff sections at and adjacent to Kimmeridge Bay, Dorset. It seems likely that at least nine of these bands form persistent markers throughout southern and eastern England. The coccolithophorid assemblages are discussed and some species of Stradnerlithus are systematically described.

The four groups of tektites are now widely regarded as the product of splash from a meteoritic or cometary impact melt of terrestrial rock. They include two groups (Moldavites and Ivory Coast tektites) attributed to the Nordlinger Ries and Bosumtwi craters. These craters seem unlikely to be of impact origin, though hyper-explosive. Tektites are, therefore, more probably all wholly terrestrial. For much the largest group, those of the combined Southeast Asian-Australian strewnfield, no satisfactory source is known. An origin in Southeast Asia, even by impact, is improbable. A possible source lies in Central Asia. The hyper-explosive activity is regarded as an extreme form of volcanism, a consequence locally and rarely of the continual combined vertical and ‘horizontal’ movements of continents, here termed tribulation.

The Durn Hill Quartzite of Redhythe Point, near Portsoy, can be divided into an eastern shear zone and a western foliated zone. The latter region is typical of most quartzites between the coast and Keith. NW-SE trending flexures, pure shear folding and wrench faults, interfere with the dominantly NE-SW trending folds of the steep limb of the Boyndie Syncline. Possible large scale NW-SE trending monoclines were identified at Redhaven, Aberchirder and Rothes. Such structures bring down the older fold axial traces and isograds towards the NE.

The palaeomagnetism of continental red beds is considered in the light of evidence concerning the diagenetic origin of various textural phases of hematite. The relative roles of pigmentary hematite and specularite as magnetization carriers is discussed and it is concluded that all magnetizations are post-depositional: the magnetization of continental red beds is therefore of diagenetic origin.

Three types of non-viscous magnetization, A, B and C, are recognized in continental red beds. Type-A magnetizations retain some features of the original magnetization and are most closely coincident with the depositional age of the rocks. Type-B are composite magnetizations acquired over a long period (more than 108 yr) of time and after substantial changes in the ambient geomagnetic field. Type-C magnetizations bear no relationship to the depositional age of the rocks and represent the ultimate end-product of the diagenetic processes which affect continental red beds. Thus, these magnetizations represent stages in the diagenetic evolution of red beds. The rate of diagenetic evolution, and hence of the modification of the magnetization, is variable and depends on a variety of local geological variables.

The study enables some assessment of the reliability of palaeomagnetic data from red beds. Type-A magnetizations, although of diagenetic origin, are considered to be palaeomagnetically reliable, but only within certain limits. Red beds with Type-B and Type-C magnetizations are not considered to be generally suitable for palaeomagnetic study. Palaeomagnetic studies are, however, considered to have great potential value for dating specific diagenetic processes in continental red beds.

It was recently proposed that the base of the Jurassic system be taken at the base of the Blue Lias in the Watchet area of Somerset thus including the underlying White Lias in the Triassic System. The mapped base of the Blue Lias however is a diachronous horizon ranging from pre-planorbis Beds age in Somerset to Schlotheimia angulata Zone age in Warwickshire. No certain chronological correlation is possible between the base of the Blue Lias in the Watchet area and any limestone or other horizon in the pre-planorbis Beds elsewhere nor is there even a palaeontological separation associated with this horizon. This paper reiterates established Geological Survey practice of taking the Triassic-Jurassic boundary in Great Britain at the top of the Cotham Beds and thus including the White Lias limestones in the Lower Lias. The White Lias limestones are regarded as a local shallow-water facies of the pre-planorbis Beds since they both contain similar non-ammonitiferous marine macrofossil assemblages;the Cotham Beds provide palaeontological separation since they divide theseassemblages from the different marine macrofossil assemblages found in the Lower Rhaetic Westbury Beds and also contain the boundary between the Rhaetipollis and Heliosporites miospore zones. The lacustrine or lagoonal Cotham Beds are similar in lithology to the Tea Green Marl and also include reddened beds of mudstone like those of the Keuper Marl; they are therefore better contained in the continental Triassic system rather than the marine Jurassic system.

Iron-titanium oxides from Taberg in Sweden exhibit under the electron microscope several microstructural features not visible when studied by optical microscopy, including homogeneous nucleation of magnetitess from ulvöspinelss, and the spinodal decomposition of magnetitesss. Such microstructures have promise as indicators of cooling rates.