A new stratigraphic scale of the USSR Precambrian officially adopted by the All-Union Precambrian Meeting in Ufa (1977) and approved by the National Stratigraphic Committee (1978) is discussed. Archean and Proterozoic have been distinguished in the Precambrian, the boundary between being 2600 Ma. Proterozoic is subdivided into the Lower- and Upper-Proterozoic with the boundary between them 1650 Ma. Riphean and Vendian are distinguished in the Upper Proterozoic. More detailed subdivisions of the Upper Proterozoic are Burzyanian, Yurmatian, Karatavian, Kudashian and Vendian. Lithological and palaeontological characteristics of these subdivisions and their radiometric age are given.

The Upper Westphalian succession in the National Coal Board's Eastling Wood Borehole, 1976 ‘TR 6303 1472’ has been analysed in terms of upward-fining and upward-coarsening semicycles, transition probabilities and entropies. This analysis confirms that the succession can be divided into a lower coal facies, which like the earlier Westphalian deposits of Kent was laid down dominantly in deltas but which includes numerous channel-fills, and an upper channel facies laid down in a more upstream fluvial environment.

Fabrics in migmatites from Portsoy in the NE Dalradian are compared with those in paratectonic and pretectonic migmatites from deeper structural levels of the Northern Grampain Caledonides. Paratectonic leucosomes, from Portsoy and Mid-Strathspey, have weak biotite fabrics. They lack the biotite foliation which is strongly developed in pretectonic leucosomes from the Upper Findhorn area. In conjunction with the sequence of deformation, intrusion and metamorphism in Banffshire, the fabric data indicate that migmatization at Portsoy was paratectonic with respect to the local F, folding. Partial melts generated in the aureole of the pre-F3 basic intrusions were, in some rocks, still mobile during F3 and completely crystalline only after the formation of small F3 folds. Granitic leucosomes in Mid-Strathspey were formed within the time-span of a deformation episode. Petrographic measurements show that these leucosomes have approximately minimum-melting compositions in Qz-Ab-An-Or, despite some deformation and retrograde alteration. They are comparable with the Portsoy migmatites in grain size and in complexity of leucosome shapes, and they are tentatively interpreted as products of incipient partial melting without dehydration of biotite.

Paleontological and petrological studies of clay beds in the Basilika Formation (Tertiary age) are presented. The petrology of the beds indicates that their main constituents were derived from volcanic activity and represent bentonites. Differing composition between beds suggests several spatially separated eruptions. The volcanic source area probably lay towards the N of the present Tertiary outcrops of Svalbard. Two foraminiferal assemblages are found in the bentonites: the lower is dominated by arenaceous forms while the upper consists of calcareous species.

Chloritoid-biotite- and chloritoid-staurolite-bearing rocks occur around Blair Atholl, Perthshire. Textures suggest staurolite to be produced from chloritoid by a prograde ionic reaction involving muscovite. Chloritoid rocks are aluminous, lying above the muscovite-chlorite join, and staurolite formation involves the breakdown of chloritoid and muscovite. Their presence indicates that the chloritoid-biotite zone of Stonehaven continues as far SW as Central Perthshire, although its occurrence is severely limited by a lack of aluminium-rich rocks. The use of the chloritoid outcrop in the NE as an indication of pressure decrease to the SW is therefore queried.

An experimental investigation into the formation of crystallographically orientated etch pits on quartz sand grains was undertaken. The methods and materials used in the experiments differ considerably from those of other workers in this field. Using natural as opposed to artificial solutions, V-shaped or triangular etch pits as well as rectangular pits have been produced on the quartz grains after time periods of 4 hours and 20 hours. Features of intense surface disintegration have also been recorded. The etch pits are compared to those of natural occurrence on grains from the Millstone Grit (Namurian) sediments and the differences discussed.

Carbonaceous dirt bands containing some 40% hydroxyapatite and 10% kaolinite are recorded from the Hornlo seam of the Brynammon district of the South Wales coalfield with an appreciable areal extension. X.R.D. and some chemical data are recorded. The origin of the deposits is ultimately biogenic, possibly located by the porous environment provided by fusinite; but the immediate cause remains uncertain.

Blebs of anorthoclase-phyric purple rock, usually up to 10 cm but occasionally up to 30 cm in diameter, occur in trachyte lavas of the volcanoes Kilombe and Kapkut, Kenya. The blebs have bulbous outlines and chilled margins and are therefore considered to have been liquid when incorporated in the trachyte. Chemically similar to the benmoreites of Hawaii, Skye and the southern Kenya Rift Valley, they bridge a gap in an otherwise complete sequence of lavas from basalt to trachyte. The failure of benmoreite to erupt as a lava is attributed to viscosity reaching a maximum among intermediate lavas.