In the Kongsberg-Bamble series of South Norway leucocratic albitites are associated with amphibolites. The plagioclase of the albitites is An2-An13, that of the amphibolites is commonly An28-An40. The metamorphic facies is upper almandine amphibolite and the inferred P. T. conditions are about 700° C. and 7,000 to 8,000 bars. Recent experimental work indicates that at these temperatures and pressures amphibolites will begin to melt and the first liquid will be of albitic composition. It is suggested that the albitites owe their origin to the partial fusion of their enclosing amphibolites.

A small mass consisting of three intrusions of fine-textured acid rocks occurs within the basaltic agglomerates of the Kilchrist Vent of Tertiary age. One of the intrusions comprises flow-layered rhyolite and ignimbrite. It is thought that the rock-types represent two distinctive eruptive waves. A form of ovoidal structure not seen elsewhere in the Kilchrist area occurs in another rhyolite intrusion.

Chemical analyses of dolerites and metadolerites from the Scourie-Loch Laxford area have been made, together with analyses of amphiboles and a pyroxene from these rocks.

Chemical variation within the dykes as originally emplaced has been investigated. Introduction of material during metamorphism is limited, only potassium showing a marked increase in concentration. In the least-altered dykes a relationship between degree of clouding in felspar and amount of H2O+ present is indicated.

Chemical analyses and optical properties of amphiboles show no distinctive trends which could be associated with the progress of the metamorphism.

The mineral cordierite occurs in Pre-Cambrian gneisses, granulites, and granites of the Guyana Shield in British Guiana. In the Acid Biotite Gneisses and Acid Granulites forming the Kanuku Group, the mineral was formed during regional metamorphism. Considerable enrichment of cordierite occurs in the contact aureole around the South Savanna Granite. Cordierite of xenocrystal origin also occurs in the South Savanna Granite and its apophyses. The 2V and optic sign of the mineral varies widely, and no definite pattern in relation to the paragenesis of the mineral is recognized. Untwinned cordierites are predominant in regionally metamorphosed rocks while lamellar, interpenetration and sector twins are characteristic of cordierites in contact hornfelsed aureole rocks.

The Caledonian dykes fall into two age groups, one older than the Newry complex and the other younger, and these have been compared with the Older and Younger Series of Caledonian dykes from the Ards Peninsula (Reynolds, 1931), which are older and younger respectively than the cleavage movements affecting the Silurian sediments. The suggestion is therefore made that the emplacement of the Newry complex and the cleavage movements in the Ards Peninsula were temporally associated events.

The Caledonian dykes are older than the joints in both the complex and the sediments, while the Tertiary dykes are younger.

A number of coarse-grained blocks, consisting of forsteritic olivine, chrome-diopside, calcic plagioclase, and chromite in varying proportions, were found in an ankaramitic basalt on Faial. With one exception, the blocks show remarkably little alteration. There is no evidence of zoning in any of the minerals. Indications of strain are frequent. Dark scoriaceous material is often present along intercrystal boundaries and fractures. The textures and gradations in composition suggest that these blocks were formed by crystal accumulation.

Methods are outlined by which density changes due to burial and compaction can be studied, and results are briefly discussed of an application of these methods to New Red Sandstone rocks from the English Midlands. From density measurements on surface rocks and compaction tests on a disaggregated sandstone it is concluded that there is no significant increase in density with depth down to 10,000 feet if the original, depositional, porosity of the sediment is low. Compaction tests suggest that sands with a high original porosity will, over a similar depth range, undergo permanent (i.e. non-elastic) deformation producing a 10 per cent increase in density.

Arising from detailed reassessment of field work in the area of Ny Friesland and Olav V Land from 1938 to 1965, a revised stratigraphical scheme is proposed for the Hecla Hoek succession which is known to range downward from Lower Ordovician and Lower Cambrian (1 km.) into a relatively unbroken sequence of Pre-Cambrian rocks about 19 km. thick. The metamorphosed older rocks, previously grouped as Lower Hecla Hoek, are reinterpreted as a succession 12 km. thick with a large volcanic component and a distinctive tillite horizon. Correlation is attempted anew with rocks elsewhere in Spitsbergen and overseas. The Hecla Hoek suite contributes to an interpretation of the development of the Caledonian tectonic province in late Pre-Cambrian and Lower Palaeozoic time.