1. The contact metamorphic effects produced by the intrusion of quartz-monzonite into the Silurian limestone of the Marulan district, New South Wales, are described.

2. The rocks are divided broadly into marbles, hornfelses, skarns, and hybrid diopside-rocks. The first two groups are interpreted as being due to the recrystallization of limestone containing impurities which have reacted with the lime of the sediments to give lime-silicates and certain other minerals. The view is taken that only a very minor amount of pneumatolytic metamorphism followed the main thermal change. The skarns are shown to be due to the metasomatic replacement of recrystallized limestone by magmatic solutions rich in iron and silica, which were also responsible for the deposition of iron-oxides in cracks.

The hybrid rocks are explained as developing from limited marginal assimilation of limestone by the quartz-monzonite magma.

THE Millstone Grit described in this paper forms a belt of country about a mile wide, stretching from west-north-west to east-south-east across the north of the Gower Peninsula. Reference is also made to small areas of Millstone Grit preserved in synclines at Oxwich and Porteynon on the south coast of Gower. These areas form the most important outcrops of this formation on the south of the South Wales Coalfield. Further east the Millstone Grit is thinner and it is not exposed for some miles to the east of Swansea Bay, as it is concealed by Mesozoic rocks.

In the Geological Magazine for February the limestone-boulders in the Bowland Shales of School Share near Settle were redescribed by Dr. R. G. S. Hudson and the writer, and the conclusion reached that they represented a landslip from a fault-scarp raised along part of the Craven Fault-system during the mid-Carboniferous earth-movement. Whilst that article was in the press the writer became aware that great limestone-boulders occur in the Caney Shale of Oklahoma and that they have occasioned much discussion or even, owing to their size and varied fossils, uncertainty as to the age of the associated beds. His interest was piqued, for he recalled that a close comparison had been drawn by Bisat between the contrast of Bowland Shale (Culm) and Yoredale facies of sedimentation, displayed in the Craven Lowlands and in the Craven Uplands and the Yorkshire Dales, and a contrast in Oklahoma between the sedimentation in the Ouachita Mountains and that in the nearby Arbuckle Mountains.

The foraminifera here described were collected by C. Barrington Brown in the course of a survey as geological member of the Anglo-Italian Boundary Commission of Somaliland in 1929–30. We are indebted to him for the opportunity of investigating these specimens and for the use of his unpublished maps and field-reports.

One of the outstanding problems of petrogenesis at the present time is that offered by the remarkable association of sharply contrasted acid and basic rocks (e.g. granite-gabbro; granophyredolerite; pitchstone-tholeiite; and rhyolite-basalt) in igneous complexes such as those of the British Tertiary Province and those of the great lopoliths of Duluth and Sudbury in North America and the Bushveld in South Africa. The contrast was first recognized in the lavas of Iceland by Bunsen (1) and it led him to the conception that two fundamental magmas, respectively acid and basic, were concerned in the genesis of the igneous rocks of Iceland and similar provinces elsewhere. Bunsen's view, however, has had little influence in the development of petrological philosophy. The petrologists of the Geological Survey in this country, and Bowen and others in North America, have assembled a very weighty and reasonable mass of field and laboratory evidence supporting the hypothesis that the acid rocks are residual products arising from the crystallization-differentiation of basaltic magmas. In the recently published Ardnamurchan Memoir (2), for example, it is claimed that as a result of the early extraction from the Plateau Magma of olivine, pyroxenes, basic plagioclase, and iron ores, the residual magma would reach a composition “which would find expression as quartz-doleritic rocks with an acid mesostasis capable of mechanical separation and a separate existence as acid lavas or intrusions” (p. 95). Bunsen's two magmas are thus regarded as successive products from a single parent stock.

OF late years, owing to the great volume of original papers sent in to the Geological Magazine, it has not been possible or desirable to devote space to the proceedings of the British Association, as was the custom under the editorship of the late Dr. Henry Woodward; but it is manifestly impossible to pass over in silence the celebration of its Centenary, which has just been held in London, under the presidency of the Right Honourable General J. C. Smuts. The personality of the President alone would be sufficient to mark this off as a special occasion, but from the point of view of the geologist there is much more in it than this.

The collection of mollusca dealt with in this paper was made by Dr. W. A. Macfadyen during his survey of the Farsan Islands, Kamaran Island, and the adjacent Arabian coast in the winter 1926–7. An account of the geology has been given by him in Part 1 of the paper, while Mr. A. G. Brighton will be contributing a section on the fossil echinoids. Dr. Macfadyen's investigation has shown that the islands are composed mainly of fossiliferous strata of late Cainozoic age. It was found possible to make out a definite succession, broken by local unconformities, and a good collection of fossils was made from each stratigraphical subdivision in the hope that definite evidence of the age of the beds would be obtained. The only previous contribution to the palaeontology of the area is a paper by Jousseaume (1888), which includes an account of twenty-five species of “raised beach” mollusca collected by Faurot on Kamaran Island. One of these—a Spondylus—is described as new, but the remainder are referred to living Indo-Pacific species. It appears from Faurot's description (1888, p. 534) that these shells came from the top bed of the Reef Limestone of Dr. Macfadyen's classification. Lists of the species present in Dr. Macfadyen's collection are given in the second part of the present paper, but these will be preceded by a short discussion of the general results of the investigation, and also of our present knowledge of the molluscan fauna of the late Cainozoic deposits of the Erythraean region.

The Ards peninsula, which forms the eastern part of Co. Down, is about 20 miles long and varies from 3 to 5 miles in breadth. On the west it is separated from the mainland by Strangford Lough, the east coast facing the Irish Sea.

THE object of the present paper is to give some geological description of the western range of the Andes, and the Tertiary formations which are developed along the Pacific coast. References are also made to the plutonic and other types of igneous rocks which are known to occur and have not been described hitherto. During the past four years the author has made a complete traverse of the Andes in Ecuador, viz, from Babahoya to Guaranda, thence to Riobamba and Baños, including the entrance to the Oriente.

The vogesites are of two distinct types, one of which will be designated type A and the other type B.

IN a previous paper in this Magazine, as well as in an official report to the Government of the Federated Malay States and in a paper in the Mining Magazine, I have discussed in some detail the geological relations of the pregranitic sedimentary rocks of the Kinta Valley, in the State of Perak, F.M.S.1 The relations of the mainly calcareous Raub Series of Permo-Carboniferous age and the rocks generally known locally and colloquially as the “ Schist Series ” (Triassic and perhaps Rhaetic), formed one of the principal subjects on which I was requested to report to the Government. My conclusions were, I think, sufficiently clearly expressed in the publications quoted, and it is unnecessary to repeat here the arguments and field evidence which led me to those conclusions.

LARGE collections of material have been brought back by numerous Arctic Expeditions, and, as many writers have pointed out, much of this raised beach material proves changes of climatic and other ecological conditions during Quaternary times. Before correlation of Quaternary deposits in Spitsbergen and other Arctic lands can become at all certain, it is essential that as many detailed contributions as possible should be made to our total collection of facts.

The recent discovery of fossil fishes in the Devonian rocks of Victoria may appear somewhat surprising in view of the fact that the general geology of the state has by now been worked out in fair detail, both by the Geological Survey and by independent investigators. Much of the detailed work has been confined, however, to the Lower Palaeozoic groups, in which the original gold deposits of the state are found, the economically less important Upper Palaeozoic rocks having been subjected to less minute examination by the Survey, especially of late years, and left in the hands of individual geologists, who often turned to the great igneous rock masses occurring in the central part of the state as constituting a congenial subject for research.

It appears that the geophysical approach to the problems of crustal dynamics leads to a theory of mountain formation that covers the main features of the formation of nappes and is in general agreement with other geological evidence. The chief novelty is in the recognition of the importance of the spreading under their own weight of the rocks uplifted as a result of crustal shortening.

The Cardiganshire coast shows various geological features of considerable interest. The present paper deals chiefly with the character and evolution of the coastal slopes and cliffs in the north of the county, between Borth and Aberayron.

SOME time ago Mr. Charles Edmonds provided me with a number of sandstones of Carboniferous age from West Cumberland to compare with the sandstones of the Peel Series in the Isle of Man. These specimens proved to have an interest peculiar to themselves which it is the purpose of this note to describe.

THE excursion to East Anglia in the week preceding the Centenary Meeting of the British Association will include visits to four of the sections of the Waltonian Red Crag at present accessible, and the occasion seems appropriate for the publication of studies which were interrupted in the year 1885 by my removal to Lancashire and were not resumed until the year 1930, after a lapse of forty-five years.

The presence of small quantities of detrital (terrigenous) minerals in the Chalk has been recorded from such widely-separated areas as Northern France (1), the Isle of Wight (2), Antrim (3), Mull (4), and East Anglia (5), but the discoveries of boulders in that formation appear to be restricted to the south-east of England. These records may be due to the greater extent of the workings in the Chalk of that area, and hence the greater frequency with which these “foreigners” are uncovered, or to some definite geographical conditions prevailing in Cretaceous times. The information available seems to prove that Betchworth has yielded more boulders than all other areas added together. In 1897, W. P. B. Stebbing (6) described two granitic rocks from that area. The present paper deals with a small collection of nineteen boulders made by the late Gerard Weedon Butler, also from Betchworth. Since these notes were first drafted the writer has been informed that a collection of something like 70 boulders, mainly from Betchworth, has been added since 1912 to those that were already in the Museum of Practical Geology.

IN a previous paper in the Geological Magazine (1) the hypothesis was suggested that mountains might result from the dragging together of sediments and other rocks by a convection current inthe material below the crust. It may be useful to review the present position as to how far this idea has offered an adequate explanation of mountain and other earth structures.

Over a period of some three years Dr. A. W. Groves has been working on the correlation of intrusions by their heavy mineral content, and the results have been published in three papers which have appeared in recent volumes of the GeologicalMagazine. The three papers read seriatim provide an interesting study of the evolution of an hypothesis which, if substantiated, would remove much, and in certain favourable cases, all of the uncertainty that usually shrouds the age of an intrusive rock-body.