In 1885 a trustworthy Persian agent, through whom various antique objects had been already acquired for the British Museum, offered for sale to its authorities a so-called thunderbolt, weighing 131 lbs. (59.4 kilograms), and submitted at the same time the following translation of a Persian letter from his Excellency Hajee Ahmed Khane Sarteep, Ex-Governor- General of Bunder Abbas, Persian Gulf, and Grand Vizier of Muscat:—

Single fragment of iron, having an estimated weight of eleven pounds, was found about the year 1880 on or near the top of Alleghany Mountain, 3 miles north of White Sulphur Springs, Greenbrier County, not far from the eastern border of West Virginia, U.S.A. ; this corresponds to longitude 80° 20' W. of Greenwich, latitude 37° 51' N. The finder and his official agent, thinking it a piece of rich iron ore, searched unsuccessfully for a vein : the specimen itself was taken to a country smith's shop, heated and cut with a cold chisel; the pieces were distributed as specimens of iron ore. Some time afterwards, two of them, weighing respectively 63 oz. and 31 oz., were given by the agent to Mr. Matthew A. Miller, Civil Engineer, of Richmond, Virginia ; convinced of their meteoric origin, he immediately tried to recover the pieces already distributed, but after travelling several hundred miles was forced to the conclusion that they were irrecoverably lost. From Mr. Miller the two pieces were acquired for the British Museum.

The coins referred to in this paper were received through Professor J. W. Judd, F.R.S., to whom they had been sent by Mr. George W. Shrubsole, F.G.S., Honorary Curator of the Museum belonging to the Chester Society of Natural Science.

According to Mr. Shrubsole the Roman coins of Chester are generally found in soil consisting more or less of disintegrated red sandstone and clay : the coins of the find now under consideration must have been buried for fifteen centuries, for such as have been deciphered belong to what is called the Roman Third Brass, and range from Philippus, A.D. 244, to Constantine, A.D. 887. Mr. Shrubsole further remarks that crystals are not found to result from the alteration of isolated coins ; when met with they line cavities between adjacent coins of a pile.

Some small crystals of a substance, supposed at the time to be an allotropic modification of Creatinine (C4H7N3O), were submitted to me for crystallographic determination. The crystals of which the angles were to be measured were thin elongated plates nearly of an inch long, of an inch broad, and of an inch thick.

As I was descending the Val Chisone from the Col de Sestriéres last summer, my eye was attracted by the peculiar colour of an erratic, which was lying on the hillside very near the road. The violet-blue tint, generally indicating the presence of giaucophane, was perceptible, especially in certain lights, but, as it was much less strongly marked than in rocks in which I had previously observed the mineral, I felt doubtful. However, I secured a good specimen, and now find on microscopic examination that glaucophane is present, though it is a pale coloured variety, differing from those which I have hitherto examined.

The block was a fairly large one, perhaps more than a square yard in area, and a couple of feet thick. I did not, however, take measurements, as the exact size was unimportant.

The mineral Leucite has for so long a period been considered as one of the most remarkable examples of limited distribution both in space and time, that the discovery in Australia of a rock largely composed of this mineral, by Mr. T. W. Edgeworth David, F.G.S., of the Geological Survey of New South Wales, is one that appears deserving of being at once placed upon record.

Leucite-crystals, under the head of "white garnet," or "white schorls," appear to have been known from a very early period ; and, indeed, the fine examples from Somma could scarcely fail to attract the attention of the older mineralogists. Subsequently it was found that the mineral occurs in other parts of Italy, and especially the neighbourhood of Rome, as well as at the Laacher See and the Kaiserstuhl.

The specimen which is the subject of the present note is a magnificent piece of Proustite from Chañarcilio, Chili, which has been recently acquired for the British Museum. It is a mass of lustrous crystals, measuring about 3 inches by 2½ inches, and nearly 3 inches in height.

The specimen has a peculiar cockscomb appearance, due partly to the habit of the crystals and partly to the way in which they are grouped ; the lower part consists of Proustite, interpenetrated by a little minutely crystalline white Calcite, which on one side of the specimen extends partly over the crystals in the form of darker coloured acute rhombohedra.

The discovery by my friend, Mr. Dick, of zircon, rutile, tourmaline, cyanite, &c., in the Hampstead and other sands, and also the necessities of a work in which I am engaged, have induced me within the last few weeks to turn my attention in a somewhat systematic manner to the sedimentary rocks, and especially to the clays. At present I have examined only eight or nine samples of clays, but I have already come across a fact which I trust will be thought of sufficient interest to justify this communication. In examining the clays the method I adopt differs from that followed by Thurach in his classic investigations, " Ueber das vorkommen mikroskopischer Zirkone und Titan-Mineralien in den Gesteinen, only in one respect. I examine the washings which are removed by his process.

The clays appear under many widely different aspects, and from one point of view must be studied as rocks. There are rock-masses alike of clay and of serpentine, both the result of important metamorphic processes. The basis, however, of most—probably of all—clays appears to be a substance of definite composition and well-marked characters, as much entitled to specific mineral rank as allophane or serpentine, or perhaps opal. In this paper I propose to consider clay as a rock and as a mineral.