In a traverse through part of Buckinghamshire and Bedfordshire last vacation, with the object of tracing the extent of the Cambridge Greensand, I was informed of some recently opened Coprolite works at Brickhill, near Bletchley. On further inquiry, they proved to be the “red coprolites,” a term applied by the workmen to the phosphatic nodules of the Neocomian like those of Potton and Upware (the Cambridge Greensand and Gault nodules being known as the “black coprolites”).

From time to time I have accumulated a large number of results obtained in identifying precious stones by means of their specific gravity. From these results I have selected about 70, which will be found arranged below. The observations have been made with care, and, where no temperature is given, at 15° 5 C.; an asterisk denotes those determinations in which a very accurate assay balance by Oertling was used, and in which the specimens were immersed in alcohol, not in water. In these latter determinations any error would be confined to the third place of decimals.

The typical forms of Chœtetes petropolitanus, Pander, are free in habit, and are invariably furnished with a flattened or concave base, which is covered with a thin concentrically-wrinkled epitheca. The general shape of the corallum is typically a cone or hemisphere when full-grown, and a concavo-convex disc when young; but its adult form is liable to great variations; and even the young examples are not constant, being sometimes plano-convex, or slightly bi-convex. The calices are exclusively carried upon the upper surface of the mass, and are thin-walled, polygonal in shape, and destitute of intermediate tubuli. Very often the surface exhibits minute tubercles, carrying corallites of a slightly larger size than the average; but this phenomenon does not appear to be constant. Young examples may have a diameter at their base of four or five lines, and a height of three lines; adult specimens may have a long diameter of four inches or more at the base, and a height of an inch and a half; but the majority of individuals exhibit dimensions intermediate between these measurements.

Shortly after this remarkable shower of meteorites had taken place two very full reports on the occurrence were drawn up by von Haidinger. It is computed that over a very limited area more than a thousand stones, weighing in all from 8 to 10 cwt., must have fallen. The largest found is now preserved in the Vienna Collection; it weighs 293·3 kilog. (5 cwt. 3 qrs. 3 lbs.), and measures 2ft. 4 in. long and 18 in. broad, and penetrated the ground to a depth of 11 ft. For drawings of this enormous block, the largest mass of meteoric rock preserved in any collection, and coloured representations of the meteor which was observed at the time of its descent, the reader is referred to von Haidinger's two memoirs.

When I sent the above paper to the Geological Magazine, I was not aware that a Sketch of the Geology of the Isle of Man, by Mr. John Home, F.G.S., of the Geological Survey of Scotland, had been published in the Transactions of the Edinburgh Geological Society.

In the short notice on the Drift (Geol.Mag. July, 1875, p. 328) I did not mean specially to condemn Mr. Birds; the paper being intended as a general protest against the loose nomenclature used by former writers and adopted by those of the present day.

The descriptions of two of the species enumerated in my paper on the Tertiary Fossils of the West Indies having been accidentally omitted, the defect is now supplied.

The necessity for a reform in the present nomenclature of the Drift is apparent from the different papers on the subject, but more especially from the note appended to Mr. Bird's supplementary paper on the “Post-Pliocene Formations of the Isle of.Man” (Geol. Mag. May, 1875, p. 228). The author of this paper states that this glacial drift is “generally marine.” May I ask how a drift deposited in the sea can be called glacial? Undoubtedly, originally, it was ice-formed, but so also are all the drifts or the major portion of them, that at the present day are accumulating in the seas round our islands, in our lakes, and in our river valleys; let them be shingle, gravel, sand, silt, or a boulder drift. A normal glacial drift must be deposited direct from ice.

This remarkable siderolite was found in Bohemia, at a spot not very far distant from the Saxon frontier or indeed from Rittersgrün, in Saxony, where a mass closely resembling it was almost contemporaneously found. So far back as 1751 at Steinbach, a village about midway between Breitenbach and Rittersgrün, a meteorite in all respects similar was discovered; the three masses are so similar to one another and so dissimilar to any others preserved in collections that there can be little doubt that they belong to the same fall. In 1825 Stromeyer examined a siderolite in which he found 61·8 per cent, of silica; this also appears to have been a member of this shower of meteorites, believed by Breithaupt to have been the “Eisenregen” which occurred at Whitsuntide, 1164, in Saxony, when a mass of iron fell near the town of Meissen.