Under the influence, perhaps, of the prevailing idea of evolution in all things, the conviction has been growing in the minds of geologists in recent times that the larger features of the earth's surface have grown from the earliest times, and therefore that the places of the continents and ocean-basins have been substantially permanent. Prof. Dana is largely the originator and expounder of this view, and he has applied it with great skill to the American continent. But while I believe the view is substantially true, I cannot but think that it may be, and has been, pushed too far. It is true indeed that the opponents of the view have attributed to its advocates a strictness in the use of the term ‘permanent’ which they have never urged. It is true that by permanence is meant only permanence of place, not of outline, and that substantial permanence is not inconsistent with very large changes by oscillation, especially at the end of the great Eras. But, making every allowance for such latitude of meaning, there has been, undoubtedly, some confusion of thought and looseness of statement on this subject. We give a few examples.

Dr. Bonney having been so kind as to examine microscopically and describe a collection of crystalline rocks which I made in the vicinity of Assouan on the Nile, I have prepared the following notice of the geological conditions, to accompany his descriptions, referring, however, to the notes on the locality given in my paper in the Geological Magazine for Oct. 1884. Reference may also be made to the paper of Lieut. Newbold in the Journal of the Geological Society, vol. iv., and to that of Mr. Hawkshaw in the same journal, vol. xxiii. Lartet has given in his Geology of Palestine a summary of the observations of Russegger, Rivière and Figari Bey on the crystalline rocks of the Nile, and the allied rocks of the Sinaitic Peninsula have been described by him, by Bauerman and by Holland, and more recently by Hull. All these authors have given, more or less distinctly, a series of gneisses and micaceous and hornblendic schists associated with intrusive granites and diorites as the oldest rocks of these districts, and succeeding these in geological age, certain slates and associated rocks, with porphyry and basanite in beds and veins.

I Have not deemed it necessary to examine microscopically the whole of the collection made by Sir J. W. Dawson, but have selected a series of fairly representative specimens, sufficient, I think, to give a general idea of the principal varieties. For purposes of identification I leave the reference numbers borne by the specimens, though their sequence is accidental.

The few recorded Madreporaria of the Upper Lias possess considerable interest on account of the great generic as well as specific differences which exist between them and those from the Middle and Lower Lias, though it might seem probable that the discovery of a greater number of species would diminish that discrepancy. Such a conclusion has not, however, by any means been substantiated by further acquaintance with those from the Upper Lias of the district of which I am about to speak.

The late Mr. Charles Moore in his exhaustive paper, “On the Middle and Upper Lias of the South-West of England,” gives sections of the Upper Lias exposed in quarries on the hills at Stanley and Dumbleton.

About, or nearly, forty years ago, two deep wells (with borings) were made at Brentford, which, passing through Gravel, London Clay, and the Lower London Tertiaries, reached the Chalk at a depth of about 315 feet, and were carried some way into the last.

One of these wells is at the Brewery on the southern side of the High Street, now known as the Royal Brewery, and it continued in use till its water became unfit for brewing-purposes, from the cause noted below. The other is 99 yards off, north-eastward, at some printing-works at the back of the houses on the other side of the street. This one was made for a Distillery which has long ceased to exist; the well too having been abandoned, at least for its original purpose of water-supply.

In September last, I drew the attention of the readers of the Geological Magazine (Decade III. Vol. II. pp. 412–425) to a singular group of vegetable-feeding aquatic animals, the Sirenia, represented at the present day by two genera, Manatus and Halicore, and by at most six species, three or four of which are probably only varieties. A peculiarity of this group of animals is that whereas the two living genera are distributed in the subtropical regions East and West of the African continent, and to its rivers and opposite coasts, the ancestors of the Halicore and Manatee (the Halitherium, Felsinotherium, and some ten other fossil genera of Sirenians) probably intermingled and extended 30° further north than at present from the West Indies and Carolina through England, Belgium, France, Germany, Italy, and North Africa, whilst Rhytina, the largest of them all, only became extinct 100 years ago on the shores of Behring's Island, Kamtchatka. The evidence which the fossil remains of Sirenia afford of a more northerly geographical extension of subtropical mammalia in Tertiary times, is abundantly confirmed by other genera, to one of which only, the Hippopotamus, I will here refer.