The mineral afwillite (3CaO.2SiO2.3H2O) is so far recorded only from the Kimberley Mines (Parry and Wright, Min. Mag., 1925, p. 277), where it occurs in association with natrolite, apophyllite, and calcite in a dolerite inclusion in kimberlite. Its occurrence with markedly different associations is sufficient warrant for a short record. Examination of the mineral associates of spurrite of the contact zone of the Scawt Hill dolerite Co. Antrim has revealed a second occurrence of afwillite, lining a cavity in a thin calcitic crust covering a spurrite contact rock.

It is unusual to discover specimens of Palaeozoic Brachiopoda which clearly display the characters of the delthyrium; in particular, very little is known concerning these features in Carboniferous Protremata. The writer has therefore been fortunate in obtaining well-preserved examples of Chonetes, in which the ventral pseudodeltidium and the dorsal cardinal process are exhibited in detail. It has also been found possible to determine the internal features of these structures by means of serial sections.

If there is one branch of geology that was more strongly represented than another at the Fifteenth International Geological Congress in Pretoria, it is petrology. It is true that the petrologists did not present many papers, and that their official discussions were rather scamped, but it was on the excursions that they showed their real strength. I shall not soon forget the day when I conducted a party of fifty to Pilansberg. To see them jump from the buses at every stop; to hear fifty hammers ringing at once on my favourite nepheline rocks; to see the collecting bags swelling and the buses sinking lower and lower on their springs; few sights have ever given me keener pleasure. The Franspoort-Leeuwfontein excursion was also a purely petrological occasion, in which more than fifty took part; and then at the end of the Congress some thirty of us enjoyed ten days of concentrated petrology on the Bushveld excursion, under the inspiring leadership of A. L. Hall.

In July of 1929 I visited the classic locality of Piltdown under the guidance of Sir A. Smith Woodward. After paying homage at the tomb of Eoanthropus we descended from the plateau to the low-level gravel terrace that flanks the flood-plain of the River Ouse. At a place known locally as Sharp's Bridge (marked on the accompanying map by a cross) there is a new but already extensive gravel pit. A spot-level on the map near the pit gives the approximate level of the top of the gravel terrace as 38 o.d.; the face of the pit is dug to a depth of from 8 to 10 feet below this level, and seems to reach down to about the level of saturation determined by the water of the river.

The Quaternary System has always presented peculiar difficulties to those geologists who have attempted to work out its chronology, largely owing to the fact that it is not always easy to correlate the details of one locality with those of another. In some cases at least, this appears to be due to lack of knowledge of the detailed sequence of events within a limited district, whether such a sequence is considered from the climatic or from the cultural point of view, or from a combination of both. The main object of the present paper is to enquire into the state of our knowledge concerning the Quaternary and Recent train of events which have taken place within a limited district, so that in the future this area can be compared with others which will have been treated in a similar way.

During the summer of 1929 members of the International Summer School of Geology and Natural Resources, Princeton University, had the opportunity of examining with Mr. E. B. Bailey geological sections in the South-west highlands of Scotland and assisting in the determinations of tops and bottoms of beds in certain critical areas. The subdivision of the series into formations and the distribution of these formations were already for the most part known, but some important details of the structural interpretation were in doubt. In 1924, Thorolf Vogt, after visiting the area, stated that he had determined the order of succession in parts of the folded series; but these determinations by Vogt and their implications had not been verified or accepted by Mr. Bailey by the early part of 1929. Detailed observations made by the Princeton party in 1929, on strata which admitted of top and bottom determinations on the basis of cross-bedding, channelling and texture gradations, confirmed and extended the findings of Vogt; and Mr. Bailey is now in a position to restate the structural interpretation of the South-west Highlands making use of satisfactorily determined sequences in some of the units where formerly the sequence was in doubt or had been incorrectly inferred.

In a recent paper, Dr. L. L. Fermor (12) discusses the composition of chlorophaeite and palagonite and the employment of these terms, with special reference to the present writer's view of this subject, reached principally through a study of the palagonitetuffs of Iceland (11). In an earlier extended study of Indian traps Dr. Fermor had concluded that the orange and brown chlorophaeite-like bodies, often called “palagonite” by the Indian Survey petrographers, are identical with chlorophaeite, and that the similar associated greenish substance, also embraced in the term “palagonite” by these workers, is perhaps, when anisotropic, the chlorite delessite (10, p. 133). One inference from these observations is that palagonite comprises chlorophaeite and the associated green substance; another is that the application of palagonite to these bodies was primarily a misnomer.

Of the naturally occurring forms of (Mg, Fe) SiO3, only two are of any great petrological importance. Rhombic pyroxenes of the enstatite-hypersthene series are common in many igneous rocks and in the metamorphic derivatives of these and of sediments. Members of the anthophyllite group of rhombic amphiboles are of much more restricted occurrence, being practically confined to crystalline schists and metasomatic products. The stability relationships of these forms and of the rarer monoclinic clinoenstatite and kupfferite were originally investigated by Allen, Wright, and Clement. Enstatite was obtained by crystallizing a glass below 1100° C., and anthophyllite by very rapid cooling from a melt at about 1600° C. Some uncertainty still exists, but it is clear that at least under normal pressure clinoenstatite is the only stable form.

Those who have made separations of heavy minerals from sands or crushed rocks will doubtless have realized that concentrates obtained by panning are not identical with those obtained when heavy liquids (usually bromoform) are used, for certain of the heavy minerals, either because of their shape or somewhat lower densities, tend to be washed away to a greater extent than zircon, rutile, etc. Yet, on account of the high cost of bromoform, panning is frequently adopted; and a compromise method of panning off most of the light material and completing the separation by means of bromoform is also used. As there is no record in geological literature (so far as I can trace) showing precisely to what extent the composition of the residue depends upon the method adopted, the following account may be of interest.

1. The Loch Awe Nappe succession was correctly stated in 1922.

2. The Iltay Nappe succession was correctly stated in 1922.

3. The Ballappel Foundation succession was wrongly stated in 1922.

4. The recumbent-fold structure of the Ballachulish district is due to rotation of middle limbs by drag from above or from below.

5. Graded bedding is as important as current bedding in marking a facies group among sandstones. It often indicates accumulation in rather deep water, to which sandy material has penetrated, perhaps as a result of seaquakes.