The article which appeared by Dr. Ball in the February number of the Geological Magazine (pp. 71–6), strongly urging the origin of the Egyptian Nile Valley as due to erosion rather than faulting, is the first public expression of a widespread feeling that the familiar rift theory is based on comparatively feeble foundations, and either requires strengthening or withdrawal. It must be remembered that when the Geological Survey of Egypt commenced its operations in 1896 the relation of deep African depressions to rifts was an accepted theory which had been found applicable in a number of striking instances. As one who has studied portions of the Nile Valley and the neighbouring deserts of Egypt for some years, I submit these few remarks, adopting a somewhat more personal point of view than is usual in papers of this nature, not from a desire for controversy, but because the subject is one worthy of discussion.

Novak considered this form within the range of variation of Cellepora depressa, Hag., but Canu recognizes it as a Rhagasostoma. It appears to be so closely related to a very distinct and persistent form which is very abundant and characteristic at Trimingham that I do not like to treat them as anything but two forms of a single hitherto unnamed species, and the form admirably figured by Novak must of course be the type of the species.

Dr. Hans Beck has adduced an example of a volcano which, according to him, has been formed independently of a fissure. The volcano pierces the centre of a faulted block, the Herdubreid, in Iceland, and on the vertical fault-faces there is no sign of any fissure. The example is probably unique in the world, and seems at first sight to negative the hypothesis that the escape of gases which tear through the earth's crust and form the chimneys of volcanoes is in the first place initiated by a fracture; on closer examination, however, the fact that the volcano stands in close relation to the faults which bound the horst, and the many cases which are known to occur where a fracture in the earth's crust may be healed at the surface so that the rocks about the fracture are subsequently more resistant than before, seem to point to the Herdubreid volcano being a normal fissure-formed volcano, only that it stands in the same relation to the fracture as a parasitic cone stands to the central crater. In other words, the chimney is an escape vent leading below the surface to one of the bounding faults of the horst.

When one considers the part Britons have played in exploring and investigating the various desert regions of the world, one is surprised at the relatively small amount of literature that there is in the English language dealing with the phenomena which are peculiar to desert conditions. Many hazy, and even erroneous, ideas are still held with regard to the processes at work and the effects produced by the various agents of denudation.

In a review of Mr. H. J. L. Beadnell's important Memoir on the Topography and Geology of the Fayûm Province of Egypt, published by the Egyptian Geological Survey in 1905, I briefly referred in passing to some “curious blocks of sandstone, pierced by numerous borings”, described by the author, and I added, “they appear to be the exact replica of specimens brought home from Lake Tanganyika by Mr. J. E. S. Moore” (p. 519).

Two well-preserved Teleostean fishes from the Eocene Limestone of Tura, between Heluan and Cairo, have been submitted to me by Dr. W. F. Hume, Director of the Geological Survey of Egypt. They apparently represent new species, but, like most fishes of Eocene age, they are remarkably modern in type, and one seems to be referable to an existing genus. With them were found remains of two species of Percoid fishes, which are scarcely sufficient for exact determination.

In 1905 trenches for electric mains were carried up the northeastern slope of Shooters Hill, along Shrewsbury Lane to “The Bull”, and thence down the western hill-slope along the Dover Road. From about 350 O.D. in Plum Lane to 424 O.D. at “The Bull” the trench ran for nearly two-thirds of a mile along the junction of the London Clay with the overlying group of sands, pebbles, and clayey gravels which form the ‘gravel cap’ of Shooters Hill. Neither the exact age of these superficial deposits nor their mode of formation—whether marine or fluviatile beds—is as yet known, but the general coarseness of the sands, the presence of pebbles of Lower Greensand chert, and the very stiff clayey matrix of the gravel distinguish them from typical Bagshot Beds, and moreover throughout the greater part of the section a sharp and irregular junction could be traced between them and the brown London Clay. At a few points, however, the top of the London Clay was seen to pass into pale-brown and yellowish sandy clays, sometimes of significant thickness. Thus in the Dover Road, about 100 yards above Christ Church, below the thick red clayey gravel of the ‘cap’, lay about 3 feet of yellow loam, the lower part of which became a pale-brown clay passing quite gradually into normal blue or brown London Clay with septarian nodules. In the same series of excavations (1905) a trench at the junction of Shrewsbury Lane with the Dover Road showed the Shooters Hill gravel resting irregularly on a bed of fine clean yellowish sand quite unlike anything previously noted in the numerous pits and trenches opened upon the Hill, but as unfortunately the trench was only a few feet deep the relation of this fine sand to the London Clay could not then be made out.

Many years ago the late Mr. Townshend M. Hall, F.G.S., of Pilton, Barnstaple, specially devoted his energies to the geology and palæontology of the Devonian rocks of North Devon, and in addition to a set of fossils acquired from him, now in the British Museum (Natural History), he left a series of local fossils to the Museum in the Athenæum at Barnstaple. This collection has been kindly curated by Mr. J. G. Hamling, F.G.S., of The Close, Barnstaple, North Devon, who takes a deep interest in the geology of the district. Mr. Hamling has called my attention to an interesting specimen in this collection which proves to be a pygidium of Bronteus, collected by the late Mr. Townshend M. Hall in the Devonian rocks of Gerolstein in the Eifel, which country he had visited many years ago in company with the late Mr. John Edward Lee, F.G.S., of Torquay. In remembrance of that excursion Mr. Hall had presented the counterpart of this fossil to Mr. J. E. Lee, and it was supposed to be in this gentleman's collection, but it cannot now be found. There is, I believe, a good cast of the fossil in the Townshend Hall Collection in the Natural History Museum.

For a detailed study of the earthquakes of any district, an interval of twenty-one years is too brief. Long-period variations of frequency cannot be established. We can form no satisfactory conception of the distribution of seismic energy in space, for some foci may lie inactive for a much longer time, while others may continue in operation without apparent change. But, to ascertain the characteristic features of the earthquakes, to investigate their relations with those which precede and follow them, or to trace their connexion with the structure of the central districts, such an interval is possibly of sufficient length. In any case, the defects resulting from its brevity may be partly compensated by uniformity in treatment and in the methods of investigation.