In a previous paper published in this Magazine, I gave reasons for the belief that neither the Gulf of Suez nor the valley of the Nile owes its origin to trough-faulting, as was at that time generally supposed. The skeleton of the argument was as follows:—

1. Extensive faulting at the faces of the scarps of the Nile Valley and Gulf of Suez cannot be held to be evidence of trough-faulting, since the same can be observed along the scarps of the Wadi Araba, the structure of whose floor shows it to be an eroded anticline, and the faults along its scarp-faces to be merely huge landslips.

2. The faulting observable immediately along the coast of the Gulf of Suez is of an exactly similar nature to that above mentioned, and along part at least of the gulf the strata dip away from the sea on the opposite coasts, leading to the inference that the Gulf of Suez is, like the Wadi Araba, an eroded anticline.

3. If it be granted that the Gulf of Suez is not a trough-fault, the argument against the Nile Valley being a trough-fault is strengthened, the support of parallelism being removed.

It is a common feature of the dolerite dykes in Rhodesia, especially where they penetrate the great granite masses of the country, that they show, even in hand-specimens, the presence of quartz. Usually this quartz occurs in good-sized corroded fragments which are quite obviously xenoliths derived from the surrounding rocks. Of this a fine example is to be seen close to Bulawayo Railway Station, where a small dyke is at one point so full of quartz fragments, up to several inches across, as to resemble a conglomerate more than an igneous rock. Other parts of this same dyke and many other basic dykes throughout the country contain quartz, either in separate granules or in the form of micropegmatite, whose origin is not so clear. It is with a view to elucidating this point that the present notes have been put together. They deal entirely with two intrusions cutting the great Matopo granite mass. The relative ages of the dykes and the granite cannot be given in precise terms, as the data are much too imperfect.

Sir Henry Howorth in his Ice or Water deals in considerable detail with the various theories of glacier motion which have been propounded. His works are veritable mines of information concerning the subject of ice and water, and he is everywhere anxious to give all workers credit for the work they have done, to state their theories correctly, and if he should differ from their conclusions to do so in a kindly spirit. Among other theories of glacier motion he refers to the one for which I am responsible. Referring to this theory he says—

“In the Philosophical Magazine for 1888 Mr. Deeley propounded what he claimed to be a new theory of glacier motion. In this paper he very rightly says ‘that every change of outline suffered by a glacier, if we disregard melting and the small internal changes of bulk produced by pressure, etc., is due to the shear of ice plane over ice plane’. He further says of glacier motion: ‘We have, therefore, two kinds of motion—one a bodily slide in a downward direction, and another due to the differential motion of the ice not in contact with the ground.’ In order to explain the latter he postulates that constant liquefaction and resolidification is taking place within a glacier by the sun’s heat penetrating it and melting certain portions, and inasmuch as a glacier has a tendency to sink in consequence of its gravity, the liquefying of certain portions of its interior will take away the support of the rest and let it sink down.

The accompanying sketch is from a photograph taken in April, 1906, of a series of landslips just east of Chilton Chine, near Brixton, on the south coast of the Isle of Wight. The cliff, which

is composed of Brick-earth on gravel and this overlying Weald Clay, had fallen away in a series of blocks of triangular section, which were alternately base and apex uppermost; the apices in places were quite acute, and one could stride from base to base over the sharply denned apex of a clay triangle. The bases of these triangles were the grassed surface, and the apices of toughened and slickensided Brick-earth which stood up, perhaps, 4 feet beyond the grass; where the apex would naturally have been higher it was usually broken away and crumbled down. There were spaces between the blocks large enough for a horse to fall down and as much as 15 feet deep, at which depth the talus blocked the view. These spaces were overhung by the triangle that stood on its apex, so that the surface contour of my section is correct. At the time the photograph was taken the landslide was quite new, that is, small pieces of clay were falling from the overhanging faces and the fractures of grass and clay looked perfectly fresh. Possibly it had only occurred a few hours previously.

Although the remains of pedunculated Cirripedes are comparatively rare in the Chalk of England, especially in its lower zones, one can, by careful collecting extended over a number of years, get together a fair series of the detached valves of the capitulum. Thus a very fine series of Cirripede remains has been accumulated by Dr. H. P. Blackmore, F.G.S., from the upper zones of the Chalk near Salisbury. This collection, which, through the kindness of Dr. Blackmore, I have lately had the opportunity of examining, is especially rich in the valves of Scalpellum fossula, Darwin, and S. maximum (J. de C. Sowerby).

In an article published in a recent number of this journal, Dr. Henry Woodward discusses the origin of the curious cylindrical cavities which occur in such profusion in certain concretionary blocks of sandstone and on exposed rock-surfaces at two distinct levels in one or two localities in the Fayûm depression. These perforated rocks, first noted by Schweinfurth, were examined by me some ten years ago and referred to as “apparently the work of marine boring mollusca” in my memoir on the region in question. Both Dr. Schweinfurth and I had considerable misgivings in regarding the cavities in question as shellborings, but in my case, and I believe in his also, this explanation appeared to involve fewer difficulties than any other which suggested itself.