The remains of Birds from Quaternary deposits in this country have been so rarely recorded, that any fresh evidence, throwing light upon our Pleistocene avian fauna, cannot but be of interest. The specimen about to be described was found in the “Mundesley River Bed,” from whence was obtained the Emys lutaria described in this Magazine in 1879 (Dec. II. Vol. VI. p. 304). In a note appended to that paper, Mr. H. B. Woodward has given a short account of this Mundesley deposit, and it will be found fully described in the Geological Survey Memoir, by Mr. C. Reid, “On the Geology of the Country around Cromer,” pp. 119 and 126.

The Cheviot district is largely composed of those quartzless porphyritic rocks to which the term porphyrite has been applied both by English and Continental petrologists. The Cheviot porphyrites are characterized by a compact felsitic ground-mass, throughout which are scattered numerous crystals of felspar, mostly belonging to triclinic species. The ground-mass varies in colour; the two principal shades being dark purple and red. These porphyrites are evidently more or less altered rocks and sometimes the alteration has been carried so far as to make it almost, if not quite impossible to recognize their original nature by macroscopic examination. Amygdaloidal varieties are not uncommon, and in these agates are frequently found. In addition to the ordinary porphyrites, there occur masses of volcanic ash and breccia, and also a remarkable rock which has been called pitchstone-porphyrite. This is dark almost black in colour, with a well-marked resinous lustre and a specific gravity lying between 2·53 and 2·62. It is porphyritic in texture; the large crystals consisting of a fresh glassy-looking triclinic felspar. Red veins usually traverse the rock in different directions. The boulders lying in the streams are covered with a thin light-coloured crust due to weathering, but at a distance of a quarter of an inch from the surface, or even less, the fresh unaltered rock is always found.

The determination, by means of the chemist's balance, of the specific gravity of rocks and minerals, now more than ever an important element in their classification, is an operation of some difficulty. Various instruments of different kinds have been devised to obtain the same results more easily and expeditiously, and as amongst these there is one I had constructed some time ago and of which I have lately had very favourable reports from practical workers, perhaps an account of it may interest some of the readers of the Geological Magazine.

Reference is sometimes made, in the course of the active discussion of the Glacial age in the Geological Magazine, to the Pleistocene of Canada, a country which, perhaps, as much as any other, in its great extent from the Atlantic to the Pacific, and from latitude 45° to the Arctic Sea, affords opportunities for the study of the deposits of this period. It has occurred to me, in connexion with this, that it might be useful to your readers to present to them a short summary of Canadian facts, as I think I have established them in publications on this subject, which are, perhaps, better known in this country than in England.

These difficulties are assuredly most embarrassing for those who conclude that the shell-beds point to the positions where they are found having once been the sea-bottom, and especially for those who argue that its submergence and re-emergence were the result of causes operating for thousands of years. We must remember that if Sir Charles Lyell's calculations are of any value, they understate the problem, for many of the shells found in these beds are not littoral, but deep-water shells, and the land must not only have sunk to the level of the sea, but much below, to render it a fit habitat for them. We are to believe, then, that a whole continent, which was submerged for ages in this way, has nothing left to show the fact save these shreds left at different levels and always near the present coast-lines. In regard to the differing levels at which they occur, my acute friend, Mr. Darbishire, well says:—

Having gained a general comprehension of the probable physical and palæontological sequence among the Lower Palæozoic strata of the Southern Uplands of Scotland, as partly published in my memoirs upon the “Moffat Series,” and the Girvan Succession, I felt myself at liberty last summer to commence the study of those rocks of the North-west Highlands, which are supposed to be of corresponding age.