Some rocks exposed near Laig Farm, Isle of Eigg, have previously been referred to the Upper Oxfordian. In this paper their age is shown by foraminifera to be Upper Cretaceous, their petrology described and their stratigraphical significance discussed. Evidence is presented that the supposed unconformity below the Lower Corallian of North-West Scotland does not exist.

Variants of the 1959–60 eruptions of Kilauea are compared chemically with the preceding flank eruptions of 1955.

The writer was asked to examine samples of the Laig Gorge Beds to try to determine from the micro-fauna whether or not the rock was of Jurassic age, as previously thought, or younger. Seven rock samples taken from various levels within the limestone and underlying sandstone were sectioned and examined, namely:—

Laboratory measurements of the effect of a confining pressure on the strength and stress-strain characteristics of a metallurgical coking coal are described. Several-fold increases in the strength, the Young's modulus and the elastic strain at failure were found as the confining pressure was increased to 5,000 lb./n.2. The results are discussed in relation to various criteria of failure. It was found that failure was represented by Coulomb's equation relating shear stress and normal stress, provided the observed angles of fracture were not influenced by local edge stress concentrations.

Quartz-magnetite rocks occur as lenses in an area of migmatitic mica gneiss and have acted as resisters to deformation as well as migmatization. Due to plastic deformation in the enclosing gneisses a quartzite lens now strikes perpendicular to the trend of other resisters which are abruptly truncated.

Chemical and optical data for eighteen granulite facies pyroxene pairs are compared. Compositions and tie-line trends derived from optical data are shown to be unreliable and it is recommended that no attempt be made to subdivide the granulite facies on the basis of optically derived tie-lines.

A detailed account is given of the stratigraphical succession of the Chatwall Flags and Sandstone of the type area in South Shropshire, and a restricted use of the name “Chatwall Sandstone” is proposed.

The two-dimensional theory of two simple generalizations of the Coulomb-Navier criterion for shear failure is developed. The first of these refers to a material with a single plane of weakness which has a different shear strength and coefficient of internal friction from the remainder of the material. In this case it is shown that failure may take place, according to circumstances, either in the plane of weakness or in planes cutting across it. The second criterion refers to a layered material whose shear strength varies continuously from a maximum in one direction to a minimum in the perpendicular direction. In this case it appears that, instead of the two directions of failure possible for an isotropic material, there is only one possible plane of failure which lies between the plane of minimum shear strength and the nearest to it of the two Coulomb-Navier planes. Numerical results are given for the case of uniaxial compression and experimental results are shown to be in reasonable agreement with them.

Petrofabric analysis has been carried out on Carboniferous rocks involved in thrust masses of the Benton system in Pembrokeshire. Evidence is contributed, which indicates stages of fracturing and crystallographic control in the deformation of individual quarts grains.

Geological studies in eastern Singhbhum and critical analysis of Dunn's published work in surrounding regions suggest that during the Archaean times a volcanic geanticlinal arc, now represented by the Dalma lavas, tuffs and agglomerates extended roughly east–west for more than 150 miles. The geosynclinal trough in the southern, concave side of the arc was filled with argillaceous sediments, thin subgraywackes and orthoquartzites derived from a land mass to the south. The trough in the northern, convex side of the arc was filled with a huge thickness of argillaceous sediments associated with graywackes, siliceous limestones, sandstones and pre-orogenic ultra-basic and basic intrusives. Both the troughs near their border with the volcanic arc were filled with pyroclastic materials.

During orogenic movements two anticlinoria were formed in the supracrustal sediments above the two troughs separated by a syncline above the geanticline, with a granulite-migmatite core in the heart of the outer geosyncline.

The quantitative distribution of the alpha particle activity in rocks and minerals by nuclear emulsion techniques is applied to some exceptionally fine-grained rocks. The distribution of radioactivity is comparable to that observed in the coarser-grained rock types more suitable to nuclear emulsion studies.

The form of the Beinn an Dubhaich granite was considered by Harker to be boss-like. Here evidence is put forward to suggest that it may have the form of a sheet emplaced along the Torridonian-Cambrian thrust plane. The alternative hypothesis has the merit of avoiding the serious difficulties appreciated by Harker regarding the mode of emplacement of the granite.

A locality in the Moine series at which well preserved currentbedding may be viewed in three dimensions is described. An analysis of the foreset dip directions shows that the sediment was deposited by current flowing in a direction slightly east of north. The form of the current-bedding is described and the significance of the observations briefly discussed.

Tretaspis moeldenensis sp. nov. from “Bala Limestone” of Carmarthenshire is described. Almost identical forms previously referred to T. kiaeri Størmer and T. aff. kiaeri occur in the Calymene Beds of Northern England. The trilobite previously described as T. cf. kiaeri from the Phillipsinella parabola Zone of the Ashgill Series of North Wales is discussed and thought to be another new species.