Annular mounds of clinkery lava encircling shallow depressions floored with similar lava were recently discovered by the late A. D. Combe in S.W. Uganda. From their morphological, petrographic, and chemical peculiarities, here described, it is inferred that they represent transfusion products of superficial tuff occupying the sites of unusually hot fumaroles. The dominant added materials are found to be iron oxides, TiO2, K2O, and P2O5. It is suggested that the P2O5, which is abnormally abundant, may have been derived from bone beds in the underlying Kaiso Series.

Marine Lower Lias, with Ammonites bucklandi and other fossils, was recorded in the Wadi Araba by Figari Bey in 1864. No one has since been able to find marine Lias in Egypt, but in 1915 Greco figured a Sinemurian faunule, including an Arnioceras, from the Figari Egyptian collections at Florence, and claimed that Figari's discovery was confirmed. A special search for the locality was made in 1951, without success. The paper reviews the evidence and records Carboniferous rocks and fossils that were found. Some general remarks are also made on the structure and origin of the Wadi Araba.

A review is offered of some of the conclusions reached by Teall and his Survey colleagues on the Lewisian Complex of the North-West Highlands, especially such as have been strengthened by recent work by Sutton and Watson. In other directions support is given to Peach and Gunn's view that the Loch Maree sediments are later than the Scourie Dykes and not, as dough tentatively suggested, intruded by sills fed from these dykes; also new hypotheses are advanced concerning Laxfordian folding of the Scourie Dykes at Loch Maree, and Caledonian thrusting of Assynt type of Lewisian over Laxford type at Durness.

Geological work and drilling in the Western Uganda Rift since 1939 points wholly to the formation of this feature by gradual sinking of the floor. No evidence of compression has been obtained.

In this review of the Downtonian Eurypterida of Perton, Here-fordshire, a new genus Salteropterus and a new family Hugh-milleriidae are proposed, and the family Pterygotidae accordingly emended. Hitherto unknown morphological details of the Perton Eurypterida are described and discussed.

A review of the progress of knowledge concerning the Moine Schists shows that, whereas about twenty years ago many geologists supported Horne's contention that the Moine sediments were pre-Torridonian, there has been recently a marked swing towards Peach's view that they are the equivalents of the Torridonian. The interpretation of the structural petrology of these schists in the light of this change of opinion is then discussed.

New floral and lithological evidence from the tongue of Coal Measures extending from the Wyre Forest Coalfield into the northern part of the Abberley Chain establishes that the eastward overturning along the Malvern axis is of late- or post-Morganian age. Minor folding along this axis may have taken place prior to the deposition of the Upper Coal Measures. This, however, had little topographic effect as during the deposition of the Upper Coal Measures the northern end of the Malvern axis remained an area of relatively rapid subsidence.

The effects of current action on the distribution of foraminiferal tests are discussed and evaluated. The distributions of current- drifted and indigenous foraminiferal tests are compared and contrasted. A simple method of plotting abundance data facilitating differentiation between current-drifted and indigenous forms has been developed and applied to assemblages from the Pliocene Coralline Crag of Sutton, Suffolk. It has been found that these assemblages do not represent the original biocoenoses, but consist largely of exotic forms.

Preliminary observations indicate that the rhythmically varied layers of ultrabasic rock in Rhum form part of a layered intrusion built up from below rather than a series of separate injections.

The only fossiliferous representative of the Jurassic system reported to exist in Fezzan (Libya) is the thin freshwater limestone of Murzuch, which is supposed to be Purbeckian. Professor A. Desio (1938) first attributed this deposit to the Mesozoic and dubiously to the Cretaceous, but Pagni (1938) identified from it the Purbeckian gastropod Valvata helicoides Forbes and the Purbeckian plant Chara jaccardi Heer. On the strength of these determinations Professor Desio (1939, 1942) later stated that the Murzuch Limestone “should perhaps be referred to the lacustrine Upper Jurassic (Purbeckian)”. The gastro-pods, as shown in the figures by Pagni, however, do not resemble the true Valvata helicoides de Loriol ex Forbes MS. (refigured Arkell, 1941, p. 89, figs. 14 a, b, 60, 61, 62). During 1950 I pointed this out to Professor Desio. He kindly allows me to record that he as always doubtful about the age of the Murzuch Limestone and that he now considers it to be much younger, perhaps Pliocene.

The neontological concept of a species as a group of “unit populations” divided into geographical races or subspecies is applied to the palaeontological record, and the intrinsic similarities of geographical and chronological subspecies are discussed. It is concluded that the variety and the subspecies are different entities both of which have value in palaeontology. Quantitative measures of the level of specific and subspecific distinction are proposed.

The metamorphism of Pre-Cambrian dolerites in the Northwest Highlands is described and compared with that of basic rocks in the Southwest Highlands, Banffshire and other regions. The first products of metamorphism are not the same in every area. It is suggested that the trend of regional metamorphism differs according to the environment in which it took place, and that a sequence of changes established in one area cannot be used as a standard by which to judge the changes in other areas. In particular, rocks of high metamorphic grade have not invariably passed through stages characterized by low-grade minerals.

Thecal modifications in certain Monograptids are discussed on a basis of restorations which distinguish the theca from the remainder of the “thecal segment” of Törnquist. There seems little support in those bi-form Monograptids examined for the view that the less modified thecae reflect an incomplete development, and in general the new thecal types appear to represent transformations which commonly originate proximally or at least are more highly developed proximally. A possible analogy between this colonial development and metamerism is suggested.

White marble in Glen Dessarry, West Highlands of Scotland, occurs as three lenses associated with schists and calc-silicate rocks. The minerals identified in all these rocks are apatite, biotite, calcite, chondrodite, clinochlore, clinozoisite, diopsidic-pyroxene, dolomite, epidote, forsterite, garnet, hornblende, magnetite, phlogopite, plagioclase, potash-feldspar, pyrites, quartz, scapolite, sillimanite, sphene, vesuvianite, zoisite.

Two parageneses may be distinguished. One, due to high-grade regional metamorphism, apparently with little or no introduction of material, is a diopsidic-pyroxene, forsterite, phlogopite, calcite, dolomite association forming white marble. The other association occurs as veinlets and small irregular bodies in the white marble. It appears to be due to circulating solutions in which pyroxene and forsterite were unstable. Minerals of this paragenesis include potash-feldspar, plagioclase, scapolite, hornblende, minerals of the epidote group, calcite, and quartz. In certain localities scapolite formed at the expense of plagioclase and was succeeded by crystallization of epidote.

Diopside-skarns, epidote-skarns, and garnet-skarns together with very coarse amphibole-rocks are produced at the contact of limestone and epidiorite by diffusion of trondhjemitic material along the contact. The amphibole-rocks are unusual types, for the formation which material may have been drawn from the epidiorite side the contact.

A description is given of the geology of the northern portion of the Ruwenzori Mountains. The rocks consist chiefly of a migmatitic series of biotite-gneiss passing to plagioclase-amphibolite uncomformably overlying these are rare occurrences of a slightly metamorphosed series of conglomerates, grits, quartzites, and tale-schists. The area is bounded by rift faults which strike N.N.E.– S.S.W. and the strike of the gneiss series is in general parallel to that direction with a steep westerly dip. Major rift faults arc described and evidence given to show that they are rejuvenations of Pre-Cambrian fault lines. Dextral tear-fault movement is implied with superimposed vertical component. Evidence indicates that faulting took place under compressional stress in Pre-Cambrian times, but that tension supervened at the later stages under light load. A steeply dipping faulting system striking W.N.W.–E.S.E. is also present, and has resulted in the southern blocks rising relative to the northern: in this system also, early compressional stress has been superseded by tension.

During the Permian the time involved in orogeny, erosion and deposition of continental and marine deposits, and the evolution of its characteristic faunas and floras, is comparable with that of other established Systems. The Permian in the Midlands has been for many years officially classed with the Carboniferous or Trias, in some cases with a query, separated by a great unconformity. It is now urged that it should be separately represented, and include all the deposits in the Midlands from the base of the Enville Beds to the top of the “Dune Sandstone”, now called Lower Mottled Sandstone of the Trias.

An account is given of a new minor structural feature recently found in the Forest Marble of Bladon, Oxfordshire, resembling Pit and Mound structure, and various suggestions as to its mode of origin are discussed.

The morvan theory with slight modification fits the structure of the coasts of south-western Britain better than the fault theory of Atlantic coasts advanced by Suess.

The English Channel and St. George's Channel have been long in existence, and are more probably of tectonic than erosional origin.

Erosional deepening of the valleys which were drowned by the Flandrian transgression to become estuaries must have taken place almost entirely in glacial ages when the level of the ocean has been low. The tempo of coastal erosion, both subaerial and marine, has been rather slow, however, owing to the great width of the continental shelf. Thus shoreline details survive from an interglacial age.

In regions with a narrower continental shelf, deepening and also extensive enlargement of valleys across coastal lands have taken place in each glacial age of low ocean level, and interglacial aggradations have determined terrace levels at consistent heights in the inland valleys of large rivers, as exemplified in Portugal.

The cliffs of Cornwall and Wales show traces of two cycles or marine retrogradation separated by a withdrawal of the sea. Thus the “bevel”, or “coastal slope” above modem cliffs can be accounted for as an ancient sea-cliff graded subaerially during the period of low ocean level.

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.