Three areas in peninsular India are described in which the geometric orientation of the drainage pattern has led to the location of a system of parallel crustal fractures. One area is in the Archaean basement of South India. The remainder are located on Deccan basalts. The fractures are not as a rule accompanied by fault displacements, and are regarded as planes of shearing. The shearing in the Deccan basalts cuts across the post-lava dykes, and is considered to coincide with late magmatic mineralization and the break-up of the Gondwana continent in mid-Tertiary times.

A graptolite fauna, found in cherty shales interbedded with volcanic rocks south of Charlestown, Co. Mayo, indicates an Arenig age.

It is argued that the Strollamus outcrop of Tertiary basalt lavas reaching south to Coire Garbh occupies a volcanic inbreak or sink dating from the lava period; and that the Broadford Dolerite is not metamorphic.

Tear faults cutting the Barnesmore Granite in County Donegal are described. The Lough Belshade fault trends N.E.–S.W., and there has been a lateral movement along it in a left-handed or sinistral sense of 2·2 miles; it is believed to be of the same age as the Great Glen Fault. The Barnes Lough Fault crosses and displaces the Lough Belshade fracture, and may be, in part at least, Tertiary. Although the movement along it is much smaller, it has taken place in the opposite sense.

It is possible, from study of twinned calcite grains in a thin section of marble, to locate the most probable positions of the applied stresses likely to have caused the twinning. By this means inferences may be drawn as to the stress system operative during the late stage deformation of the marble.

Marble outcrops over an area of about 5 square miles, in the Tomintoul region of the Scottish Highlands, have been investigated. It has been found that a consistent stress pattern exists for the area as a whole. The calcite twinning can best be explained by a N.E.–S.W. compression applied normal to the trend of the regional fold axis, followed by a mild N.–S. squeeze.

Optical examination of the potash feldspars in the granitic gneisses of the Carn Chuinneag-Inchbae complex suggests that both ortho-clase and microcline occur together—not infrequently in the same crystal. Optic axial and extinction angles, intermediate in value between those characteristic of the two polymorphs, have been recorded and plotted graphically. X-ray powder diffraction patterns confirm that both orthoclase and microcline are present together in these rocks. It is believed that most of the microcline developed from orthoclase during the regional metamorphism of the area, which permitted recrystallization at a lower temperature than that at which the orthoclase was formed.

Peridotite, troctolite, and olivine-gabbro are exposed in the Bourtie area at the eastern end of the Insch igneous mass. The distribution of outcrops suggests that the rocks are disposed in bands running north and south and a smaller-scale north-south banding can be seen in some exposures. The earlier view that the ultrabasic rocks form an east-west lens on the floor of a northerly-dipping gabbro sheet is therefore abandoned and both the northern and southern contacts are believed to be part of the roof of the igneous body.

Regional studies using certain minerals as indices of metamprphic grade indicate a coincidence between areas of granitic injection or migmatitization and the distribution of sillimanite. Occurrences of that mineral in knotted bodies or faserkiesel and in pegmatites and aplites within migmatites have, however, sometimes been attributed to late metasomatism rather than to metamorphic conditions. In view of the doubtful value of the mineral as an index of metamorphic grade in these circumstances its distribution in the Kenya Basement System is reviewed and the field relationships between sillimanite-bearing metamorphosed pelitic sediments and faserkiesel migmatites occurring in central Kenya are described.

It is concluded that sillimanite in the migmatites is derived from partly assimilated sillimanite gneisses, which are of extensive but inconspicuous distribution in the non-migmatitized Basement System. The regional stability of sillimanite rather than kyanite over a great area suggests that high-grade metamorphic conditions prevalent in Kenya during Basement System times were accompanied by granitization processes culminating in the local formation of replacive granites in which sillimanite relics are preserved.

The lithological and faunal successions of some 1,150 feet of Carboniferous beds exposed on Foynes Island, County Limerick, are described and shown to be of Namurian Age. The stratigraphical position of Reticuloceras subreticulatum (Foord) and Homoceratoides divaricatus (Hind) has been ascertained by collecting from the type localities on the island. The palaeogeographical implications of the succession are discussed.

It has been claimed that the hinge of one of the two major recumbent folds of the S.W. Highlands is exposed near Ben Lui. In this paper it is claimed that the form of the outcrops permits the existence of this recumbent fold only if the fold-axis plunges towards the south-west. Evidence is given that the plunge is in fact towards the west, and on this basis a profile has been constructed to illustrate the observed geometrical relationships of the rocks.

The new genus Idosocrinus is proposed for a remarkable type of crinoid occurring in the Thornton Burn section of the Calciferous Sandstone Series (Lower Carboniferous) of East Lothian, and two species are recognized. In general habitus the new genus resembles Phanocrinus Kirk, but differs in the character of the left and right posterior primibrachs, which extend outward from the cup in the form of strongly developed spines. Two new specimens of Anemetocrinus wilsoni Wright are also figured.

The finding of Anthraconauta tenuis (Davies and Trueman) at Etruria, North Staffordshire, just above the basal limestone of the Newcastle-under-Lyme Beds suggests that the base of the Tenuis Zone, hitherto placed at the base of the Keele Beds, should be brought down to the base of the Newcastle-under-Lyme Beds.