The chemical differences which exist between the Moine and Torridonian rocks of the Scottish Highlands are of the same nature and order of magnitude as those between extreme end members of the Norwegian Sparagmite Formation. It is concluded that in Scotland, as in Norway, a unilateral trend of sedimentary differentiation operated from north-west to south-east across the direction of the Caledonian geosyncline and led to chemical grading of the arenaceous sediments transverse to the trend of the late Pre-Cambrian depositional basin.

The London Clay exposures on the coasts of Essex and Suffolk are described and their fossils listed. Correlation is made with similar strata in Germany and Denmark, and the significance of all these beds in relation to the Lower Eocene palaeogeography of North-Western Europe is indicated.

The best known exposures of Rhaetic strata in Glamorgan are those of the Lavernock and Penarth cliff sections, where the normal black shales—thin limestones facies are displayed. In the central and west Vale of Glamorgan, however, massive sandstones are the dominant Rhaetic formation. The construction of a housing site has revealed the presence of numerous voids or cavities in these sandstones, the origin of which is attributed to decalcification.

The stages of progressive thermal metamorphism of siliceous carbonate sediments covering mineral assemblages revealed in the highest grades of alteration were first delineated by Bowen (1940) in a paper which presented an illuminating systematic treatment of the whole subject. In his account the successive stages in the metamorphism of siliceous limestones and dolomites were, in general, linked with a series of reactions of increasing decarbonation in which thirteen steps were traced, involving the appearance of ten distinct mineral phases. With certain reservations these phases could be accepted as indicators of a temperature grade of metamorphism. Investigations carried out since that time have served to confirm the general validity of the scheme set out which thus brings law and order into a field of metamorphism characterized by considerable mineralogical and petrographical complexity.

Nodules of “pseudodiorite”, i.e. metamorphosed calcareous concretions, occur in the Lower Birrimian (Pre-Cambrian) quartz-biotite schists which are interpreted as having been calcareous muds and silts. The probable metamorphic history of these nodules is traced.

Study of profiles, perpendicular to the fold-axes, shows that the folding is disharmonic. Nearly every s−surface is one of décollement. In some exposures the quartzites are reduplicated by superposed recumbent-folds without infolds of other material. The contacts are tectonic and not stratigraphic. Incipient boudinage is frequent, and nearly all surfaces show well-developed b−lineation.

The Punjab Saline Series has been assigned to the Cambrian and also to the Eocene. Gee has described field evidence which points to a Cambrian age, but Sahni has found microscopic plant and insect remains which have been interpreted as demonstrating an Eocene age. The application of Schultze's technique (also adopted by Sahni) to samples from the undoubted Cambrian rocks of the Salt Range has shown that these too occasionally contain a microflora which includes elements that are not so far known to be indigenous to Cambrian rocks. Its occurrence awaits explanation.

A description is given of a nearly complete specimen of a new Ordovician eurypterid genus belonging to the family Stylonuridae. The classification of the Eurypterida is discussed; two super-families and two new families are proposed and three new names substituted for pre-occupied generic names.

The possibility of interaction between the alkalies in cement and flint and chalcedony has made it necessary to investigate the constitution of these minerals. It had always been thought that these minerals were a mixture of quartz and opal, but experiments have led to the belief that this is not true and that the minerals are composed of a quartz network with a large number of micropores.

Simple arithmetical techniques are set out whereby planimetric data, of the kind used in constructing area-height diagrams, can be made to yield additional quantitative information useful in description and comparison of relief. The most useful is an expression for mean available relief, which takes account of the form as well as of the height of interfluves. It is also shown how the depth of dissection of a datum surface can be mapped and measured.

It is shown that mylonite is extremely rare in the plane of the Great Glen fault, and that horizontal slickensides or friction-grooves directed along the Glen are virtually absent. Grave doubt is consequently thrown on the alleged horizontal displacement in the fault zone.

The paper draws attention to the existence in the Tertiary of Australia of three distinctive though not consecutive foraminiferal zones. The lowest zone, found in Victoria and South Australia, is of Upper Eocene age, the upper zone is not younger than Lower Miocene (Burdigalian) and the intermediate zone of Victoriella, corresponding to strata usually referred to the “Janjukian”, probably Upper Oligocene (Chattian) to Aquitanian.

The interglacial gravel at Swanscombe includes pebbles apparently derived from Shropshire and neighbouring districts; and as some of these occur in the “Plateau Drift” near Oxford, they may have reached the Lower Thames by way of Moreton and Goring Gaps. The earlier of the two boulder clays of Essex and Hertfordshire probably contributed some erratics to the Swanscombe gravels, but the later includes material from North Britain and Scandinavia unknown in the Swanscombe deposits. Therefore the gravels at Swanscombe seem to be intermediate in age between the Lowestoft and Gipping Glaciations of East Anglia, with which the two Essex boulder clays are correlated.

Tunnels constructed in connection with hydro-electric development near the head of Glen Tromie cut Moinian granulites and semi-pelitic schists penetrated by pegmatites and by quartz-porphyry and felsite sills. Deep and very extensive deposits of glacial drift are also present. A remarkable feature of the latter is the presence of hollow chambers well below the surface which are interpreted as partially collapsed moulds of buried blocks of ice.

An epidiorite sill emplaced in quartzites becomes charged with xenoliths of quartzite and of an amphibole-rich rock possibly derived from underlying limestone horizons. The matrix of the xenolith-rich part of the sill is studied with large hornblende-biotite “crystals” that may represent small limestone xenoliths that have been basified and homogenized.

In the outer zone of the Sutherland Migmatite Complex, four-inch garnets are developed in “veins” in garnetiferous rocks which, adjacent to the “veins”, are devoid of garnet. The redistribution of material has been brought about by activity along certain privileged paths. Comparison is made with the gigantic 3-ft. garnets of the Adirondacks.

In the Arkaig district of Inverness-shire there is a well-defined suite of camptonite-monchiquite dykes, and several of them have been observed to be displaced laterally along sinistral faults. This provides direct evidence of transcurrent faulting in Permian or post-Permian times. Similar faulting may have occurred along the major northeasterly fracture lines of the Highlands.

Neglect of the oldest and most useful theory of scale models in geology. Its fundamental psychological value for a correct mental picture of the earth's larger aspects.

The exact theory made more comprehensible. Its application in the domain of experimental tectonics improved upon.

A xenolith composed essentially of green pyroxene, microperthitic potash felspar, sphene, apatite, and iron ore, has been discovered in the diorite of the Glenelg-Ratagain igneous complex. it is believed to be an impregnated skarn rock associated with igneous activity earlier than the intrusion of the diorite. Introduction of P, Ti, and Na is considered to be important in the formation of the skarn.

A description is given of a monchiquite vent which cuts Moine rocks in Inverness-shire. Similar vents considered to be of Permian age are common in the Midland Valley of Scotland and the Orkney Islands but no example has yet been described in detail from the Highlands.