The Geological Survey Map of CornwalI shews, to the south of the town of St. Austell, several patches of “greenstone,” extending from near the ancient earthwork called Trethullan Castle, on the west, to the sea at St. Austell Bay in the east ; a distance of over four miles.

The western end of the most extensive of these patches swells ont on the top of the hill to the north-east of St. Mewan Church, so as to cover several hundred acres (including some of the best land in the parish). This was described by Mr. J. Arthur Phillips some years since in the Philosophical Magazine. Mr. Phillips speaks of the rock as being distinctly crystalline, consisting of felspar (sometimes triclinic) ; semi-transparent yellowish-brown crystals, probably hornblende ; a green fibrous mineral also believed to be a variety of hornblende ; many black grains of oxide of iron and a few hexagonal crystals, probably apatite ; and he says the rock exhibits unmistakeable evidence of extensive alteration. Speaking of its extension eastward, he says “it extends in diminished proportions in a southeasterly direction to the sea at Duporth.”

Mr. Readwin stated that since reading his former paper (Mill Mag., No. 5), he had visited the museums of Copenhagen, Stockholm, Christiania, Kongsberg, and London, in search of corroborative evidences of “Recent Mineral-growth at ordinary temperatures, under ordinary conditions,” and that he was satisfied that mineral “growth under ordinary conditions,” is not of unusual occurrence, .although, hitherto, neither generally observed, nor believed.

Mr. Readwin also stated that several of the specimens referred to in his former paper, some of which he took on his journey, exhibited changes and developments during his absence.

In conclusion, Mr. Readwin submitted an idea of Metal-growth more closely at home.

A tendency to assume crystalline forms is a property of all crystalloids ; its full or imperfect development depends on external circumstances.

Crystals produced in laboratories are generally inferior to natural crystals of the same substances, prohaby because of their too rapid formation. The faculty of crystallization is modified by specific dispositions inherent to the substances. There are many distinct types of crystallization, connected with each other by intermediate types, and even with a transition from amorphous to crystallizable substances.

The degree of distinctness of crystals constitutes a fundamental difference. The crystals of many substances are distinct, while below a certain limit of size ; but when this is exceeded, the surfaces are interrupted by re-entering angles, or by irregular drusy cavities or excrescences constantly re-appearing when cleft away, so as, at last, to completely destroy their individuality and regularity.

This mineral occurs in fibrous masses occupying fissures or shrinkage cracks in the serpentine of Duporth, near St. Austell, Cornwall. The thickest veins I have seen are not more than 1 1/2 inches. The fibres are placed transversely across the vein, making generally an angle with the walls of about 70°, so that the crystallization is probably oblique.

The mineral is greenish to brownish gray, has a silky lustre, H about 2 and Sp. Gr. 2.78 : insoluble in HCl, but the iron and magnesia are slowly dissolved out.

Thin fibres are flexible like asbestos. Heated in a matrass the mineral gives off a little water, and becomes lighter coloured ; in forceps thin fibres fuse to a dark glass in the hottest part of the flame. The spectroscope shews the sodium and calcium lines distinctly, but no trace of potassium or lithium.

So far as I am aware no account of the microscopic structure of this rare and beautiful rock has yet been published. I have, therefore, thought that a brief description of its structure and some considerations concerning the origin of tourmaline rocks may be of interest to petrologists.

Boulders of the rock, as is well known, are abundant in the vicinity of the village of Luxullian (about five miles from the town of St. Austell, Cornwall), where I collected specimens in tho autumn of 1873; but I believe the rock itself has never been discovered in situ, though veins of different varieties of tourmaline rock are abundant in the granite of this and other districts in Cornwall, some of which occasionally rather resemble it, and the mineral frequently occurs in the granite itself, the felsite cleans, and the altered sedimentary rocks.

The Silver-mines, near Kongsberg, in Norway, are said to have been worked unceasingly for the last 200 years or more.

On June 6th, last, I was fortunate in being allowed to visit these celebrated mines, and also the silver-works at Kongsberg. More fortunate still, in obtaining the present beautiful specimens of native silver and Argentitc. They had very recently been taken from the mines, and I was told that my visit was opportune, because such specimens were not of every day occurrence. Be this, as it may, they are of especial interest just now, as illustrating the theory of “metal-growth,” and the more particularly so, as two of them have most obligingly, since they came into my possession, thrown out sundry hints of bodily activity. In fact, have “grown”; and, as they have a direct bearing upon a previous paper, I propose to describe them as well as I can.

When investigating the constitution of antunite or lime-uranite, I secured an extremely fine specimen (of what was then supposed to be this mineral) from the mine at Falkenstein in the Saxon Voigtlaud. I was puzzled by the low percentage of water and other anomalous results which my analysis of the specimen in question gave. While at work upon the solution of this difficulty, Weisbach's note upon uranocircite or baryta-uranite appeared, Winkler's analysis of the Falkenstein mineral clearly proves that we have in it a pure baryta-uranite—a new species of the uran-mica group. I did not, however, abandon my own researches into the nature of this mineral, for the mode in which the water was held by this mineral remained unknown. If isomorphous with autunite, it might be expected to contain 10 aq. in the molecule, 2 of which would probably be retained at 100° C.

One of the blast furnaces at the the Eglinton Iron Works, Kilwinning, having been blown out, it was noticed that on the hearth there was a curious deposit of a bluish black semi-metallic colour, which by its brittleness seemed to be a slag. Mr. Smith having forwarded to my friend Mr. John Young, F.G.S, a sample of the substance, it was submitted to me for analysis and examination. On a cursory examination it was seen that it was not homogeneous but consisted of different substances mixed, the most conspicuous being the bluish substance with a plumbago lustre before referred to. On powdering it the substance was round to contain pieces of metallic iron in irregular masses inbedded in the matrix.

In making an examination of some samples of Phosphorite, recently discovered in Southern Russia, I was much struck by the unusual appearance of the substance, and after a closer examination came to the conclusion that it was a new form of the mineral, and ought to be brought before the notice of this society, in order that its occurrence and physical structure might be recorded and discussed.

The mineral which forms the subject of this paper occurs in rounded masses, varying in size from 5 to 9 inches in diameter. The outer surface is smooth and presents an appearance highly suggestive of the form being due to the action of running water, but upon fracturing several of these balls I found in every instance that they were c6mposed of a number of fibres radiating from the centre, of small size, and of a blueish grey colour, having a hardness of about 4.

In commencing the proceedings of the second Annual Meeting of the Mineralogical Society of Great Britain and Ireland, allow me to express the pleasure which it gives me to be present here to-day, and my regret that I was not able to attend the first meeting last year at Glasgow. I feel it to be incumbent on me to give some opening address, but at the same time it must not be long, since many other subjects claim attention.

In the first place I think I may well congratulate the Society on its present condition, and contrast it with some of the predictions made little more than a year ago. We were told by men well-known in the mineralogical world that no such Society as our own could possibly be established—that, even if it could, it would be of no use, unless it published a Journal—which it most certainly never could afford.

The district to which the following notes refer is contained in sheets 26 and 27 of the one inch Ordnance Survey Maps, and embraces an area of about 985 square miles, the northern boundary being formed by the Bristol channel, and that on the south by a line drawn through the town of Okehampton. The rocks composing this district belong to the Devonian and Carboniferous systems, with the exception of a small portion of new red sandstone and a patch of Greensand, occupying a few acres. The two older systems present a regular sequence of beds from north to south, which, interrupted by the granite of Dartmoor, are represented to a greater or less extent by a similar series in the southern portion of the county.

Through the kindness of Prof. and Mr. John Young, F.G.S., I have been enabled to examine a number of unclassed minerals belonging to the Hunterian Collection in the Museum of the University of Glasgow. Among them I have found some whose composition differs from anything already described, and it is with the hope that mineralogists may be enabled to identify them elsewhere, that I now publish a detailed account of them. I am sorry that it is impossible for me to state the localities of some of the minerals, owing to the fact that they were unnumbered and unknown specimens, which were found in olcl drawers of the museum when the collection was being removed to the new buildings, but as the minerals with which they are associated are characteristic, we may obtain some clue to the deposits in which they originally lay. I shall describe the minerals in the order of their complexity, giving the least complex the first place.

“Plants live, and grow ; Animals live, grow, and move; Minerals, neither live, grow, nor move.”

For so long a time, has this been an article of almost universal belief, that any nonconformity therewith, is looked upon with more or less of grave suspicion.

In what follows, it is proposed to show that there is a rather more natural order in which the aphorism may appropriately run; namely :—

Minerals grow, Plants live and grow, Animals live, grow, and move at will. “The three kingdoms of nature,” as they are not at all inconveniently called, exist in close relationship; so very close, indeed, that some naturalists think they are not really apart from each other.