The Permo-Carboniferous quartz-dolerites of central Scotland are generally holocrystalline, and only two intrusions amongst them with a fresh vitreous base have been recorded—those of Dalmeny in West Lothian, andKinkellnear Kirkintilloch (northof Glasgow). Both rocks have already been described briefly, but in view of their many interesting features a more thorough treatment seems desirable, particularly as they have a bearing on some recent theories of magmatie differentiation advanced by Dr. C. N. Fenner.

The suite of dikes that forms the subject of this paper is bounded on the south from Sleights Moor (south of Whitby) to Dalston (south of Carlisle) by the well-known series of dikes known collectively as the Cleveland-Cockfield-Armathwaite dike, and on the north by the nearly parallel and more continuous Acklington dike which stretchesfrom Bondicarr near Coquet Island across the southern margin of the Cheviots into Scotland.

In the Autumn of 1928 Dr. Béla Fülöpp and Mr. G. Kupás sent for examination an unknown mineral, which had been found in no. III level on the main lode of the Kereszthegy mine at Nagybánya, comitat Szatmár [now Baia Mare, Satul-Mare, Romania]. The small crystals show a close resemblance to those of plagionite from Wolfsberg in the Harz Mountains, but the results of our detailed examination prove that we have here a new mineral. For this we propose the name Fülöppite in honour of Dr. B. Fülöpp, an enthusiastic collector of minerals and a generous patron of the Magyar Nemzeti Mfizeum (Hungarian National Museum).

The mineral now briefly described occurs as a rare constituent of the zone of hybrid rocks formed by assimilation of limestone by the dolerite intrusion at Scawt Hill, Co. Antrim. It is found particularly in intimate association with the melilite-bearing types of this hybrid zone and is a constituent of some of the late-formed vesicles in these rocks. The minerals associated with it in the vesicles are chiefly calcite, thomsonite, and another zeolitic mineral as yet undetermined. These vesicles are most frequently enclosed by a ground rich in melilite, or they may occur within large crystals of melilite. In some cases the mineral forms minute venules cutting through the melilite, suggesting that it is derived in part by attack of residual solutions upon the melilite itself. All the evidence clearly indicates that the mineral is among the latest products of consolidation of the hybrid zone.

In examining mineral grains either from sands or from crushed rocks it is frequently found that the electromagnet not only affords a means of separating certain minerals, but is also an aid to their identification. Yet an electromagnetic separation is rarely, if ever, complete, and minerals are frequently found to stray into fractions to which they do not rightly belong. As a result, a grain which, let us say, is found in the garnet fraction may be practically nonmagnetic, and if we assume that its magnetic properties are similar to those of garnet, a misidentification may be made. It seems desirable, therefore, that there should be some means of testing the magnetic properties of a single grain.

In 1865 A. Breithaupt described a new mineral from Herrengrund, Hungary, to which he gave the name of fauserite. It formed very pale pink crystalline aggregates and prismatic crystals, with prism angle near 88°42′ (over a), apparently orthorhombic, and cleavage b(010). Two other prisms with angles (over a) 54°39′ and 107° 50′ were observed, and a pyramid p, giving mp= 52° ; these would correspond to forms (210), (340), and (111), and the angles are near those of epsomite. An analysis by Mollnár gave the figures shown under I below—a magnesium and manganese sulphate hexahydrate, with the molecular ratio MgSO4(Mn,Mg)SO4 = 31.62 %. There is no evidence that the analysed material (stated to be crystalline) was homogeneous.

The discovery of the meteoric stone near Lake Brown, County Avon, South-West Division, Western Australia, was recorded by Dr. Edward S. Simpson in the Annual Progress Report of the Geological Survey of Western Australia for 1921 (1922, p. 53). The following details concerning the meteorite are taken from that report and from a letter of September 25, 1925, sent by Dr. Simpson with the specimen, weighing 174 grams, which was presented to the British Museum collection by Mr. A. Gibb Maitland, at that time Government Geologist of Western Australia.

Since W. Lindgren first detected the presence of microphenocrysts of analcime in basalt, many observers have recorded this mineral as a constituent of igneous rocks, but there is some difficulty in distinguishing between analcime and glass and between analcime and leucite in thin rock-sections. For instance, H. Rosenbusch identified the interstitial colourless isotropic material in monchiquites as glass, whereas L. V. Pirsson showed it to be analcime. H.S. Washington showed that basalts from Sardinia, previously thought to be leueitic, contain phenocrysts of analcime. A. Lacroix also found, in his study of north African basaltic lavas, that in many cases so-called leucite-lavas actually contain analcime and not leucite.

The separator here described was designed by the author some years ago in order to avoid the tedious process of hand-picking mineral powders in front of an electromagnet. It is a complete machine dealing on a laboratory scale with the less magnetic minerals, such as monazite. For research it is essential that the separation should be clean cut ; in the present case a 90% separation of glauconite from monazite can be made in a single pass, while the removal of more widely differing minerals is complete. The machine must also deal with small samples down to 0.5 gram without loss; this necessitates a small scale and slow feed ; the time required for more bulky samples is consequently rather long, but little or no attention is required during operation. Finally, all the moving parts should be of metal and easily cleaned.

Correlated data prove the approximate constancy of the number of oxygen atoms in the unit cells of several nepheline and elaeolite specimens. Thence the number of atoms of each kind per unit cell have been counted. The cell-volumes and optical properties have slso been correlated with the chemical composition. An approximate structure is suggested which, together with the chemical work, explains the variable composition of nepheline. The contents of the unit cell may be written Si16−nAln(Na,K,½Ca)n where n ranges from 6.6 to 8.2. Kaliophilite is shown to possess a much larger cell than that of nepheline, and its Lauegram exhibits higher symmetry. 'Pseudonepheline' (rich in potassium) has a slightly greater cell-volume than normal nepheline, but its Lauegram is almost identical and its axial ratio only slightly less.

In a recent paper by Dr. W. F. Fleet and Dr. F. Smithson attention was drawn, to the occurrence of dark apatites and apatitcs with dark cores of inclusions in certain sediments of the Midlands of England, and it was pointed out that the only other definite occurrences known of these peculiar apatite grains in either igneous or sedimentary rocks appeared to be restricted to the Old Red Sandstone of the Cardiff area, the ‘newer’ granites of Jersey, and the Leinster granite. These writers also expressed the hope ‘that any future observation of such grains may be recorded with a view to tracing the source of the detrital grains of Welsh and English rocks’.

A mass of iron weighing 130 lb., stated to have been found in 1922 near the village of Piedade do Bagre in Minas Geraes, Brazil, and believed to be meteoric, was submitted by Mr. N. Medawar in January 1929 to the Mineral Department of the British Museum for examination. The following description of the mass fully confirms the supposition of its meteoric origin. Unfortunately, only scanty details are available of the circumstances of the finding of the mass. All the information that Mr. Medawar was able to supply is given in the following short note written by Mr. R. J. Bohrer, with a rough sketch-map of the locality.

Some thirty-five years or so ago small quantities of free gold were found in calcite in or near a crush-breccia filling an east and west fault, in the patch of Middle Devonian limestone which forms that portion of the coast known as Daddy Hole Plain directly south-east of Torquay. The name of the actual discoverer I have been unable to ascertain, neither do any specimens appear to have been preserved ; but the late Mr. T. Harrison, the then proprietor of the Queen's Hotel, Torquay, and several other persons subscribed about s and a small amount of prospecting work was carried out, apparently with little result. The only reference to this discovery which I know of is a brief one in 'The geology of the country around Torquay' (Mere. Geol. Survey, 1903, p. 48). To Mr. B. W. Stedham of Torquay I am indebted for the additional particulars given and also for pointing out to me the exact spot, which is on the side of a fissure formed by a large pinnacle of rock standing away from the cliff below the old quarry.

The axial system of Bravais, with three co-planar axes at 120°C to one another and a fourth at right angles to them is almost universally adopted for the description of crystals based on the hexagonal prism as unit cell. But it does not seem to have been generally recognized that the use of these axes entails some complications in respect of face- and zone-symbols. These it is the purpose of the present note to consider.

As grunerite is a somewhat uncommon mineral, and as its occurrence at Pierrefitte in association with lead and zinc ore is unusual, if not unique, it may be worth while to put on record the following notes on some material which I collected during an examination of the Pierrefitte deposits.

The name 'grunerite' was originally given to a fibrous mineral approximating in composition to FeSiO3 and occurring with magnetite and garnet at Collobrières in the dept. of Var, in the south of France, which was described by Gruner in 1847. It was originally supposed to be a pyroxene, but was later shown by Des Cloizeaux and Lacroix to belong to the amphibole group. A similar mineral occurs in the iron deposits of the Lake Superior district, and elsewhere ; but it has not been recorded from the Pyrenees.

The orientation of the ‘rhombic section’, the composition-plane of the pericline twin, in the plagioclase felspars as an index of the chemical composition of the felspar waJ first utilized by G. yore Rath, who measured the gngle a on the face (010) between the trace of the composition-plane and the edge [010,001]. Duparc and Reinhard, in their comprehensive work on the determination of the plagioclases, quote two series of values for this angle, one due to Wiilfmg and the other to Becke. They comment on the discordance between the two series, most marked at the acid end, and add that they did not then possess suitable material for critical determinations on their own account. Wülfing's values are given in the form of a curve based on data assembled by Schmidt, and those of Becke were first given in a paper on the felspars in crystalline schists.

The present note arises out of a paper by O. B. Bøggild, to which my attention was drawn recently, concerning the peculiar segregation of kamacite which gives rise to the Widmannstätten figures produced by etching plane sections of the octahedrite meteoric irons.

As the figures which occur in these meteorites are met with on a much smaller scale in many alloys, the structure to which they owe their origin must be of special interest to those engaged in the study of metals.

The zeolites form a group of minerals of considerable interest by reason of their peculiar properties. In particular, their remarkable continuous dehydration curves, in part reversible, and the ready base-exchange of some members have attracted attention. But in spite of much work, many important characters remain quite uncertain. Many of the zeolites show variations in composition which are not recognized or are incorrectly interpreted by the accepted formulae. Optical investigation has all too rarely been made on analysed material, and little is known of the variation of the optical properties of most members with their composition, and practically nothing of the variations consequent on artificial base-exchange reactions. In spite of much work, conflicting views are still held as to the interpretation of the dehydration results. In some instances even the crystal-system is still uncertain.

Introduction—pyro-electricity has been investigated by various methods. Sir David Brewster heated his crystals and brought them into contact with small, very light, insulating particles: If these adhered, the presence of pyro-electricity in the crystal was inferred. He also used a very delicately suspended brass needle. Being a conductor it was attracted to a charged crystal when this was brought near to it. Hankel placed the crystal under investigation in a small bath of copper or iron filings, which was then put into a hotair oven. The filings did not entirely cover the whole crystal, but one corner, edge, or face, whichever was required, was left exposed. A very small platinum sphere connected to an electrometer was then brought near to the exposed portion. The charge induced on the sphere was taken as a measure of the charge developed at the particular spot on the crystal opposite the platinum sphere.