Scolecite was recognized as an independent species by A. F. Gehlen and J. N. Fuchs (1813), being one of the species into which they divided, on chemical grounds, the mesotype of R. J . Haüy (1801). Its individuality has rarely been doubted, though occasionally the union of natrolite, mesolite, and scolecite into one isomorphous group has been proposed.

Three varieties of scolecite have been described, but all have proved to be other minerals. Thus poonahlite (H. J. Brooke, 1831 ; = mesolite) was long included with scolecite. Lehuntite (T. Thomson, 1836; = natrolite) was classed as a soda-scolecite by A. Kenngott (1850) solely on account of its high water content. And a mineral from Pargas, Finland, was described by N. Nordenskiöld (1821) as anhydrous scolecite (wasserfreies Scolezit); this was copied by W. Phillips (1823) as 'scolecite', and this incorrect copy appears to be the authority for the citation of Pargas as a scolecite locality by Dana and others.

In an earlier paper the writer has discussed the paragenesis - kyanite-omphacite as observed in certain ec|ogites. The fate of this association under conditions of retrograde metamorphism has led to a consideration of rocks showing the paragenesis amphibole-kyanite, a point which is briefly taken up in the present communication. Rocks containing this latter assemblage include two groups, the one better known, of sedimentary origin, the other essentially igneous in origin.

Here are included members of the para-amphibolites, biotite-hornblende- schists, and hornblende-Garbenschiefer derived from sediments of the character of calcareous and dolomitic shales. The best-known examples come from the Alps—particularly the Triassic and pre- Triassic sediments on the south side of the St. Gotthard massif.

In a previous paper (24) the writer discussed the relations between the chemical and physical properties of a number of potash-sodafelspars, mainly of the schillerized or perthitic variety, and the effect of high temperatures upon them. The present paper gives the results of further examination of these and of several additional specimens selected to make the range of composition more complete.

Twenty-six specimens were selected for this investigation. They include two albites, six microclines, and eighteen felspars which have been grouped as an orthoclase-microperthite series. The confused nomenclature of the alkali-felspars makes a choice of suitable names difficult. Alling's classification (1, pp. 253-254) represents a systematic attempt to overcome this confusion, but it seems doubtful whether some of his arbitrary subdivisions (e.g. ‘anorthoclase potentially eutectoperthite’ and ‘microcline eutectoperthite’) can exist.

The first recognition of ankerite as a British mineral seems to have been made a little over fifty years ago by M. F. Heddle, who described and analysed a sample from the Ting of Norwick, Unst. The occurrence of the mineral in veins in the Carboniferous Limestone of Lilleshall, Shropshire, was recorded by C. J. Woodward, who gives analyses of two specimens. T. Crook noted the frequent occurrence of the mineral in British coal-fields and described specimens, with two analyses, from Lancashire, Yorkshire, Nottinghamshire, Leicestershire, and South Wales. F. S. Sinnatt and his collaborators, in their work on the mineral constituents of coal, devote a good deal of attention to the 'white partings' or ankerites, of which, as they say, 'no study has appeared in the literature'.

In Haüy's original definition of eclogite, the presence of kyanite as an accessory constituent was recognized, and it is apparent that he was familiar with examples from the Sau Alps and Styria. The best known of eclogites—those of the Bavarian Fichtelgebirge (e.g. Silberbach, Weissenstein, and Eppenreuth)—contain significant kyanite interspersed among the omphacite grains or associated with accessory quartz and muscovite in the rocks. Of these rocks rather extended descriptions have been published. Analyses of the minerals and the rocks themselves belong to an early date and do not reach the standard of modern analyses. Later, Drill (1902) published a systematic account of these Bavarian eclogites and has added an analysis of an eelogite with kyanite from Unterpferdt near Silberbach and an analysis of a garnet from a Silberbach eclogite.

In a recent paper the occurrence was described of a very iron-rich orthorhombic pyroxene in thermally metamorphosed iron-rich rocks in Manchuria. The crystals are commonly 2-5 cm. in length, but some are larger, and they are accompanied by grunerite, small garnets, and disseminated magnetite. Some of these crystals are optically positive, and the following data were obtained on one crystal.

The rare barium zeolite edingtonite has been examined in the course of the systematic investigation of the zeolites now being made at the British Museum, and several substitution derivatives have been prepared. The structure of natural edingtonite has also been completely determined by X-ray methods, and in the present paper an account is given of an attempt to discover the exact positions occupied in the substituted edingtonites by the potassium and thallium ions which replace the barium ions of ordinary edingtonite.

Base-exchange products obtained from some other zeolites have already been examined in detail by X-ray methods. In silveranalcime and silver-natrolite the intensities of X-ray reflections are explained satisfactorily on the assumption that each silver ion occupies the exact position previously occupied by the sodium ion which it replaces.

IN extending earlier work on the distribution and significance of manganiferous garnet in the Dartmoor granites, the senior author found it necessary to determine whether the average composition of the Dartmoor species was fairly represented by the single complete analysis (II, below) hitherto available - that of an aggregate of garnet fragments separated from crushed tor-granite.

As a preliminary step a similar aggregate from the cordierite-rich granite exposed in the Sweltor quarry was analysed (I).

Wollastonite at Scawt Hill, Co. Antrim, ocours as a constituent of both the exogeneous and endogeneous contactzones of the dolerite. In the former it is associated only with flint nodules in the metamorphosed chalk, in the latter, however, commonly as a minor constituent of certain of the hybrid types.

In my original account a wollastonite-bearing augite-dolerite from this latter zone was figured without further description in the text (plate xvII, fig. 3). In examining the optical characters of wollastonites associated with hedenbergite, I had occasion to turn again to the wollastonites of this particular rock type.

As indicated in the explanation of the figured section (loc. cir., p. 467), the dolerite is built essentially of sharply zoned brown titanaugite, labradorite, wollastonite, iron-ores, interstitial thomsonite, analcime, and accessory sphene. In this aggregate wollastonite forms subidiomorphic crystals averaging 1 ram. in size, and from a series of sections its predominant forms can be readily made out.

The recovery of these two meteoric stones is due to the energy and resource of Mr. R. Bedford of the Kyancutta Museum, South Australia. They have been sent by him for description and placing on record, and he has very kindly allowed portions to be retained for the British Museum collection of meteorites. I also owe my thanks to him for the detailed information he has supplied respecting the finding of the specimens.

Ferrosilicon is occasionally found under circumstances that suggest that it is a natural mineral. Twice during the past quarter of a century it has been described as a new mineral, and the error was detected only after preliminary accounts had been published. It has also at times been thought to be meteoric. A supposed meteoric iron from North Carolina was described by C. U. Shepard in 1859 as composed of a material to which he gave the name 'ferrosilicine'.

The following notes collected during several years contain nothing new. They are merely brought together to serve as a warning against an error that may recur.

On several occasions between 1924 and 1929 Mr. H. N. G. Cobbe, a consulting mining engineer, sent to me for identification rounded pieces of a metallic substance that had been picked out from the concentrates of the gold dredgers on rivers and creeks in British Guiana.

This is the first meteorite to be recorded from either Southern or Northern Rhodesia. It fell at about 12.45 p.m. on March 7, 1934, on the right bank of the Shawanoya river in the Mangwendi native reserve, about forty miles east of Salisbury. The latitude and longitude of the spot are 17° 39ʹ S., 31° 36ʹ E.

The recovery of the meteorite was made through the efforts of the Rev. F. J. Gits, S.J., who is in charge of St. Paul's Mission. Three loud detonations were heard from a direction north-east of the Mission Station followed by a loud rushing sound. Father Gits, who was out in the open at the time, involuntarily ducked his head. His inquiries failed at first to elucidate the cause of the explosions, which were also heard at Arcturus, Macheke, and Mtoko, that is, over a radius of at least fifty miles.

Early in the summer of 1930 there was exposed in the Parkgate Seam, No. 3 Pit of the Manvers Main colliery, Wath-upon- Dearne, near Rotherham, Yorkshire, a large cavity lined with exceedingly beautiful crystals of baryte ; this being the first occurrence of the kind recorded in the south Yorkshire coalfield. The cavity was quickly more or less completely wrecked by the miners, when fortunately my friend, Mr. C. P. Finn, the Company's chemist, had his attention drawn to the matter, and as a result some brief notes on the occurrence, accompanied by a photograph of a specimen, were published by him. Thanks to the efforts of Mr. Finn, and as the result of visits to the colliery, I was able to obtain some very fine and interesting specimens of the mineral.

Apreliminary account of this fine mass, weighing 2520 lb., of meteoric iron was given in 1910 by L. Laybourne Smith, who at that time was Registrar of the South Australian School of Mines and Industries in Adelaide; but the promised detailed description with chemical analysis never appeared. Except for a small piece cut off one corner (upper left-hand corner in fig. 1) the mass is preserved intact in the Museum of that Institution, and none of the material appears to have been distributed to other museums. Casts of the mass were, however, made for the South Australian Museum in Adelaide, and one of them was presented to the British Museum in 1917 (B.M. 1917,360), where in the meteorite collection it is a very striking object (fig. 1).

Recently, at the suggestion of Mr. R. Bedford of the Kyancutta Museum, the Council of the South Australian School of Mines has generously presented to the British Museum a piece of this meteoric iron, together with the milling cuttings, with the request that the description of it should be completed.

The recognition of pronounced varietalism in both the garnet and the basic mica of the Dartmoor granites prompted the authors to inquire whether the cordierite associated with these species was similarly variable in composition.

The inquiry was directed in the first instance to possible variation in the optic axial angle 2V, which is determinable with accuracy on the unaltered parts of cordierite in thin rock sections. Determinations made on the sector-twinned cordierites in the garnetiferous granite of Sweltor a gave the following peculiar results, which Mr. Rama Rao verified repeatedly, using a Fedorov microscope in perfect adjustment.

The Cairnsmore of Carsphalrn igneous complex (1) is the smallest of the larger Caledonian intrusions of the Southern Uplands of Scotland. The intrusion is composite, consisting of a central granite, followed by successive zones of granite-tonalite hybrid, tonalite, and basic hybrids. The complex began with the intrusion of a gabbro. When this was crystallized, but still at a high temperature, the tonalite was emplaced. This intrusion of tonalite produced a series of hornblende-hybrids. The hybridization of the original gabbro attendant on the injection of the tonalite is the result of a 'partial magma' of potash-felspar, quartz, and volatiles. The final intrusion of granite took place while the tonalite was still incompletely crystallized, and resulted in the formation of a zone of acid hybrid rocks. The three biotites that have been analysed occur in the granite, tonalite, and hornblende-hybrid respectively.

Rocks composed mainly of the hydrated ferrous silicate greenalite are of very restricted geological and geographical distribution and, up to the present, have been recognized only from certain of the pre-Cambrian sedimentary iron-bearing formations of the Lake Superior region. It is of interest, therefore, to record an additional occurrence, not only from another region but from a later geological system.

Previous accounts of pumpellyite, a blue-gree n hydrous silicate of calcium and aluminium, are few in number; the first record is that of Palache and Vassar, who described the mineral after a study of the amygdaloidal rocks of the Keweenaw Peninsula. Later Burbank recorded a very similar occurrence in Haiti, West Indies. Again, it was observed as a constituent of veins cutting glaucophaneschists in California by Irving, Vonsen, and Gonyer, and later by Waldmann at Hochlantsch Mount, Styria, in an altered diabase, and from Lake Enare, Finnish Lapland, where it occurred in altered lime-silicate rocks. Pumpellyite was found by Quitzow in diabaseporphyrites and glaueophane-rocks from the Trias of northern Calabria, Italy.

The pyroxmangite and rhodonite, here examined by X-ray methods, are from the Lewisian schists at Glen Beag, in the Glenelg district, Inverness-shire. The material was exhibited by Prof. C. E. Tilley at the meeting of the Society on November 5, 1936, and it has since been described by him. The specimen of ‘iron-rhodonite’ was from the iron slag described by Whiteley and Hallimond, and is no. 7a in their table of analyses.

The unit cell of the ‘iron-rhodonite’ was determined by means of the Weissenberg goniometer and the data obtained are compared in table I with Gossner and Brückl's determination for rhodonite. The unit cell of pyroxmangite was determined by taking a Weissenberg photograph about the c-axis and oscillation photographs about the a- and b-axes.

Inquiry into this feature was stimulated by a reasonable doubt concerning the reality of the immiscibility gap in the clinoenstatite-diopside series. The existence of this gap was first suspected by Sosman and Asklund, and the identity of the gap with the composition field of the hornblendes has recently been suggested by Kennedy, whose comparative study of hornblende and pyroxene composition engaged statistical methods applied in the first instance by Asklund.