Muscles.—As the number and position of these organs differ materially in the two great divisions into which the Brachiopoda have been separated, and to some extent, also, in the different genera of which each division is composed, it may be desirable to treat this subject under two different heads.

The paper is divided into two parts, viz.:—

1. Sedimentary Rocks.

2. Igneous and Metamorphic Rocks.

In the year 1841 Sir R. Owen described and figured a slab of rock from the Lower Lias of Barrow-on-Soar which showed the impressions of the bones and integuments of a pelvic paddle of an Ichthyosaurus, probably referable to the typical I. communis. In this specimen it appears that the integuments were produced to a greater extent on the posterior than on the anterior side of the bony framework; and that while the anterior margin of the soft parts showed evidence of squamation, the larger posterior flap was marked by oblique striæ extending from the bones to the periphery which appeared to have been caused by parallel bundles of muscular fibres. The distal extremity of the soft fin terminated in a sharp point far below the distal bones.

It is these which afford the justification for any comparison between Sinocystis and Megacystis. Those of Sinocystis are, it will be remembered (antea, December, 1918, p. 534), a transversely elongale peristome, a hydropore-slit approximately parallel to the peristome, a gonopore to the left of the anal plane, and a hexagonal or pentagonal periproct. These openings, though differing in details, are in number and position essentially similar to those of Aristocystis. Hitherto there has been much uncertainty as to the positions, and even the presence, of the hydropore and gonopore in Megacystis. It will here be shown that both are present, and that all four openings have much the same relations as in Aristocystis and Sinocyatis, especially the latter.

Potassium–argon dates from hornblende-bearing pyroxene granulites in a large xenolith near the margin of the charnockitic Ernabella Adamellite, central Australia, are interpreted in the light of oxygen isotype studies of associated mineral phases which give a detailed thermal history of the Adamellite and associated rocks.

The only species of Scaphites hitherto identified from the Holaster planus Zone of England is S. geinitzi d’Orbigny, which occurs commonly both in the Chalk Rock and in the normal facies of the zone in many parts of the country.

In answer to the observations made by Professor King in the June number of your valuable Magazine, I am quite ready to admit that several very important points in connection with the shell-structure and interior arrangements of the Spiriferidæ have still to be determinted, and I am always delighted when some new light can be thrown upon the subject.

A Controversy apperas to be carried on between geologists as to the causes of the excavation of valleys, and the degree in which marine denudation on the one hand, or the eroding power of rain and rivers on the other, have been concerned in the process. To this controversy Mr. D. Mackintosh has contributed two papers, in recent numbers of this Magazine. I am desirous of recalling to the recollection of its readers certain facts which demonstrate, beyond the possibility of doubt, how vast is the error of those writers who, like Mr. Mackintosh, speak of “the impotence of rain as a denuding agent.”

It is often said that controversies advance science. I believe, on the contrary, that they retard it—that they are wholly mischievous, and that all good scientific work is done in silence, till done completely. For party in politics, there are some conceivable, though no tenable, reasons; but scientific controversy in its origin must be always either an effort to obscure a discovery not yet distinctly established: and it seems to me there are but two courses for a man of sense respecting disputed statements;—if the matter of them be indeed doubtful, to work at it, and put questions about it, but not argue about it; so the thing will come out in its own time, or, if it stays in, will be no stumbling-block; but if the matter of them be not doubtful, to describe the facts which prove it, and leave them for what they are worth.

Textures are important features of sandstones; however, their controlling factors are not fully understood. We present a detailed textural analysis of fluvio-lacustrine sandstones and discuss the influences of provenance and depositional environments on sandstone textures. The upper Permian – lowermost Triassic Wutonggou sandstones in the Bogda Mountains, NW China, are the focus of this study. Sandstone thin-sections were studied by point counting and their textures were analysed using statistical and principal component analysis. Fluvial lithic, fluvial feldspathic, deltaic lithic, deltaic feldspathic, littoral lithic and littoral feldspathic sandstone were classified and compared. These comparisons indicate that lithic and feldspathic sandstones from the same depositional settings have significant differences in graphic mean, graphic standard deviation and roundness; in contrast, sandstones from different depositional settings but with similar compositions have limited differences in textures. Moreover, three principal components (PCs) are recognized to explain 75% of the total variance, of which the first principal component (PC1) can explain 44%. In bivariate plots of the PCs, sandstones can be distinguished by composition where lithic and feldspathic sandstones are placed in different fields of the plots along the axis of PC1. However, sandstones from different depositional settings overlap and show no clear division. These results indicate that provenance, mainly the source lithology, is the most significant controlling factor on sandstone texture, whereas the depositional environment has limited influence. This study improves our understanding of textural characteristics of fluvio-lacustrine sandstones and their controlling factors, and shows the potentiality of principal component analysis in sandstone studies.

One of the internal contacts of a doleritic intrusion, Co. Donegal, is lined with large augite dendrites. The habit is revealed by parting on a median zone of chlorite which is regarded as an altered exsolution feature. It is suggested that an initial platy dendrite grew, in response to undercooling, as a metastable phase with the composition and structure of a high-calcic pigeonite. A later overgrowth of augite preserved the delicate crystal against destruction.

To the old volcanoes of East Fife Sir Archibald Geikie assigned a Permian age. In the course of a characteristically able series of investigations he discerned that on the shore at Lundin Links one vent had penetrated some of the highest members of the Scottish Coal Measures, whereas at Kennoway another could be seen to have risen through the Millstone Grit. There further appeared to be a general similarity in the lithologic and petrographic characters of the materials of the entire group, thus linking them together, and they seemed to have taken birth after the inception of the tectonic features of the area. Only one simple conclusion emerged from a consideration of these facts, namely, that the vents must be referable to some period of post-Carboniferous time. In support of that opinion he pointed especially to the Largo district, where he thought he could detect a sheet of fragmental volcanic material resting with a distinct unconformability upon the folded and denuded Carboniferous strata, which supposition, of course, could it be confirmed, would render further discussion upon the matter unnecessary. But in the East Fife Memoir it is stated that the sections which might be expected to furnish critical evidence are not clear.

The very fine series of fossil footprints which, at my request, Principal Dawson has kindly examined and described in the accompanying note, were discovered last summer, in Nova Scotia, under the following circumstances.

Mr. J. W. Knowles, M.R.I.A., of Ballymena, read a paper on what appeared to him to be flints chipped similarly to the eoliths, which he had found in the Interglacial gravels of Ireland. This gave rise to a discussion, in which five speakers in succession gave reasons, or rather expressed opinions, adverse to their artificial character; and as these seemed based on some misconceptions, and also as I was the only one who spoke for them, and was told I must be brief, and so could not fully reply to them, I do so in the present form, and I state, as far as I remember, what took place in as few words as possible.

Mr. Knowles himself took a neutral position, but suggested that, if they were implements at all, they might have been used as scrapers for scraping hæmatite.

The objections were: that these so-called eoliths were found in such extraordinary numbers that they might be the result of natural causes, and that their upholders must disprove this; that the flints in question were those of the Clay-with-Flints, a deposit due to the chemical dissolution of the Chalk-with-Flints; that, if admitted to be artificial, they could not be older than the Palæolithic implements of the high levels, as they were both found in the same deposits; that similar flints were to be found in the Boulder-clay, and, as man was post-Glacial, that was a positive refutation.

A small collection of fossils from the Upper Ordovician of Quarrel Hill, Girvan, made recently by Mr. James L. Begg, is remarkable for the number and character of the lamellibranchs, several of which appear to be new. Their affinities are chiefly with those of the Ordovician of the United States and are consequently of special interest.