Spongolite beds are common in the basal Namurian shales of Co. Clare and Co. Limerick, and are especially well developed north of Ardagh, Co. Limerick. Spongolites from this locality are described and are considered to represent a local deposit of siliceous monactinellid spicules. They are compared with the “phtanites” of the Assise de Chokier of Belgium, which are of the same age and similarly preserved. Stylolite seams developed within the rocks are briefly described.

Measurements were made of features formed in relation to former sea-levels along the north coast of Sutherland between Melvich and Durness. The results suggest that four raised-levels can be identified. The uppermost, which is at a greater elevation on the east, is related to glacial and fluvio-glacial deposits, which indicate its formation in close proximity to glaciers. This level has been correlated with the “100 ft.” beach. The next level also shows slight tilting up to the east and seems to correspond with the “50 ft.” level elsewhere in Scotland. The two lowest levels are horizontal, and can be correlated with the “25 ft.” and “15 ft.” levels respectively.

An extensive pumice raft was encountered by H.M.S. Protector in the area of the South Sandwich Islands on the 14th March, 1962. Evidence is presented which suggests that this material was ejected on the 5th March, 1962, from a submarine eruptive centre 35 miles to the north-west of the existing islands but on the axis of the South Sandwich Arc.

A cordierite-garnet granulite from Assam, India, carries optically positive cordierite, garnet, spinel, biotite, and sillimanite. The optics of the cordierite are: α = 1·534, β = 1·540, γ = 1·548, 2V = + 81°, while the composition of the garnet inferred from the writer's charts, in terms of the end-members, is Al73Py20Sp2An3Gr2. The development of an iron-rich garnet in association with a magnesium-rich cordierite is discussed, and data are presented to show that such garnets have a restricted compositional range. It is doubtful if the FeO/MgO ratio in a cordierite-garnet assemblage can be used for interpretation of the physical conditions governing the formation of the host rock.

The Pre-Cambrian rocks north of Three Rivers, Quebec, are cut by a major fault in which glassy pseudotachylites have been developed. The glass, which is dark brown in thin section, has a specific gravity of 2.76 and a refractive index of 1.567. It has a similarcomposition to the quartz monzonite in which it occurs. Absolute dating by the potassium-argon method indicates that the glass is 975 million years old. The persistence of thisglass indicates how sluggish devitrification can be when the environment is cool and dry.

Lava channels flanked by lava levees are described from Tristan da Cunha. These have been formed by the building up of the levees by overflow and solidification of fluid lava from the channels. A distinction is made between the terms “lava levee” and “lava moraine”.

Specimens of Pseudoclimacograptus marathonensis sp. nov., preserved in relief, from the Ordovician of Marathon, Texas, are described. An account of a series of sections of the proximal end is also given. The material is compared with the compressed syntypes and other specimens of Amplexograptus Confertus (Lapworth), with which the new species had been confused.

In the Assynt area of the North-West Highlands of Scotland a regional preferred orientation of quartz [0001]-axes of sedimentary origin in Cambrian quartzites has withstood considerable deformation and destroyed only with the onset of granulation in the immediate vicinity of thrust planes. After partial granulation the remaining scattered quartz grains develop a preferred orientation of [0001]-axes quite distinct from the sedimentary fabric. Recrystallization is apparent well away from the thrust planes, but only supersedes granulation along certain sections of the major Moine Thrust plane. The preferred orientation of quartz [0001]-axes in these recrystallized fabrics is somewhat variable. The regional quartz fabric of metamorphic origin in Moine rocks immediately above the thrust planes can experience a similar deformation, recrystallization following granulation with the development of quartz fabrics similar to those in recrystallized quartzites below the Moine Thrust plane.

The geology encountered in the driving of the Dinas Cwm-Rheidol Hydroelectric pressure tunnel is described.