In 1826, 27, and 28, Prof. Sedgwick contributed to the Geological Society of London his classical papers on the Magnesian Limestone of the East of England, in which he describes in detail the concretionary structures which occur in many of the beds of this formation in Durham.

Although he describes these concretions in minute detail, he says but little as to their probable origin, but it is clear that he regarded them as composed of carbonate of lime derived from the beds in which they occur, when he says—“The particles (of lime), after deposition, appear to have run into lumps and masses more or less crystalline, rejecting great portions of the earthy residuum.” Since Prof. Sedgwick's papers little seems to have been contributed to the subject of the mode of formation of these concretions.

In some papers which have lately appeared in the Geological Magazine, I have endeavoured to show that the Ural Mountains, and also the great masses of high land in Eastern Asia from the Altai to the Himalayas, are of very recent geological origin, and that it was probably their rapid elevation which caused the great diluvial movement of which traces are to be found all over the Siberian plains. I now wish to call attention to some of the evidence which points to the American Cordillera being also a very recent geological feature, and dating from the same period of cataclysmic revolution which closed the Mammoth age.

It is a curious fact that one name, America, connotes both of the great continents hung together by the isthmus of Panama. The cause of this is of course purely historical, and yet it coincides with a great physical fact, namely, their essential unity in more than one respect. The generic unity of the old inhabitants of both continents is a peculiar fact in ethnography; but the unity is even more remarkable in this, that the vertebral column which runs north and south through the two Americas is essentially one backbone.

The most remarkable earthquakes of the year 1890 were those felt in the district round Inverness between November 15 and December 14. These have been described in a separate paper. The remaining earthquakes were of comparatively slight intensity. Two or three were felt during the night of June 25–26 within a very small area to the north-east of Leeds, and one at least in Kintyre on July 24. Several slight shocks at Invergarry and Feddan, in Inverness-shire, complete the list so far as known to me, with the exception of a doubtful shock at Tulliallan in Perthshire on January 6.

It is hardly necessary to do more than refer here to the two supposed earthquakes felt on January 7 at and near Chelmsford. In a letter to “Nature,” I have given the evidence in full; and it appears to me sufficient to show that they were merely the reports of one of the great Woolwich guns.

In the Geological Magazine for July last the Rev. W. Andrews and Mr. Jukes-Browne gave an account of Lower Cretaceous strata in the Vale of Wardour. I can bear testimony to the correctness of this statement. Many years ago, when geologizing in the vale chiefly among the Purbecks, I found many portions of ironstone and hard ferruginous sandstone, in the fields and by the roadside both at Dinton, Teffont and especially at Chilmark, containing casts of Cyrena, Turritella, and a part of a dermal scute of a Saurian, which I believe belong to the Lower Greensand, but I never saw it in situ, and it seems to have been greatly denuded.

Until recently no outcrop of the Vectian or Lower Greensand was known to occur between Lulworth on the coast of Dorset and the neighbourhood of Devizes in Wiltshire. It was supposed that, with the exception of a small area of Wealden in the Vale of Wardour, the whole of the Lower Cretaceous Series in Dorset and South Wilts was concealed and buried beneath the overlapping Upper Cretaceous strata. A recent examination of this district however has revealed two areas where the Vectian sands emerge from beneath the Gault. One of these has already been indicated in the pages of the Geological Magazine; the other is the subject of the present communication.

The retention of the original colour-markings amongst fossil Brachiopoda is a somewhat rare occurrence: the following striking instance therefore seems worthy of record.

It is true that Deslongchamps in the Paléontologie Française mentions the colours of a number of Jurassic Brachiopods, but in nearly all these cases the colours are spoken of as if uniformly distributed and not patterned over the shells, and therefore we cannot be sure that they are original and not subsequently produced.

Of British fossil Brachiopods which show the colour-markings, Terebratula hastata and Discina nitida respectively from the Carboniferous Limestone of Longnor, Derbyshire and Hamilton, Scotland, Terebratula intermedia from the Cornbrash of Wollaston, and Terebratula biplicata from the Upper Greensand of Cambridgeshire, are examples.

The alteration undergone by the Coniston Flags, owing to the intrusion of the Shap granite, has been well and fully described by Messrs. Harker and Marr in their most able and interesting paper, read before the Geological Society in the spring of this year, “The Shap Granite and the Associated Igneous and Metamorphic Rocks” (Q.J.G.S. vol. xlvii. 1891).

I have worked a great deal, microscopically, on the rocks of this district, both before and since the publication of the results of Harker and Marr, and this work has enabled me in a special manner to appreciate the quality and value of their investigations in this complicated and interesting region. I was so fortunate, two summers ago as to spend some time at Shap with Mr. Marr, who most kindly assisted me to understand some of the problems involved, and pointed out to me the places where specimens of special interest could be collected.