The mineral to which this notice refers is obtained from New Jersey. It is very largely employed for paper-making in place of China clay (Kaolin), and gives, amongst other advantages, a much more pure effluent, fully ninety per cent. being retained in the paper. From its fibrous nature it appears to attach itself to the smaller paper particles and retain these also. The very high and beautifully smooth glaze of the American papers is largely due to the use of this substance.

The mineral is of a highly fibrous character, almost pure white, perfectly insoluble in water, is greasy to the touch, and readily broken down in the fingers.

In my description of a Glaucophane-eclogite from the val d' Aoste, I alluded to the occurrence of a rather similar rock in the Ile de Groix (off the south coast of Brittany) in the following words:—" In the Ile de Groix the glaueophane occurs in no great abundance, with greenish mica, epidote, garnet, hornblende, and but little quartz." My knowledge of the rock, as then stated, was from one or two specimens only; but in the autumn of 1886 I paid a short visit to the Ile de Groix in order to see the rock in the field. I then found that in the above phrase I had unwittingly done an injustice to this locality for glaucophane, for I obtained specimens in which that mineral is even more abundant and almost as well developed as in the rock from the Val d' Aoste. On this account, and as the locality is rarely visited, I venture to think that a few notes may be interesting to the Society, although the rock has been already excellently discussed by Dr. Charles Barrois, to whom I am much indebted for information about this and other interesting localities in Brittany.

In 1881-1882 Dr. A. Brotherus and his brother, A. H. Brotherus, made a botanical tour in Armenia and the Caucasus; the younger gentleman collected a few specimens of rocks met with during their journey, which, on his return, he kindly left to be examined by me.

This material consisted of later eruptive rocks; it was scanty, but as it was obtained in places from which we have no earlier information of a similar character, I have not thought it uncalled for to make in the following lines a slight contribution to our knowledge of the geognosy of the regions in question.

The microscopical analysis of rocks from the Caucasus made by Tsehermak, Lagorio, and Möhl relate in part to the identical rocks that I shall describe, but the localities are different.

The granite of the Cheesewring Quarry is coarse grained and grey in colour. It is essentially composed of white felspar, quartz and two micas. Tourmaline occurs sparingly. The dominant felspar is orthoclase, frequently twinned on the Carlsbad plan. Crystalline form is not well developed. Under the microscope the individual grains do not, as a rule, give detinite extinction. Different portions extinguish at slightly different angles. The arrangement of the different portions is often very irregular; sometimes, however, it gives rise to a striped structure, under crossed nieols, suggestive of micro-perthite ; but in no case has a perfectly definite intergrowth of plagioclase and orthoelase been observed. Examined by Szabo's method the orthoclase is seen to be fairly rich in soda. A well striated plagioclase occurs in the rock, but is present in very small quantity. When it does occur it is often seen to be idiomorphic with respect to quartz.

Prof. Tennant, of London, and I, identified the two "Albertites " in 1862. I was then a Commissioner for Nova Scotia at the Great Exhibition. In the ncighbouring Court of New Brunswick there was a tub full of specimens of Albertite, which were freely given to visitors by Mr. Daniel, the Commissioner for New Brunswick, and myself.

It was, therefore, no astonishment when the Professor's assistant put into my hand a piece of "Albertite" as I entered the shop, and asked me what I thought of it. I said, "It is a piece of our New Brunswick Albertite." He replied, it was not from New Brunswick, but from some part of England, and showed me a boxfull that had just been received. The only guide to the locality whence it came were the markings on the lid of the box—" Aberdeen Railway" and Kiltearn.

Some little confusion having apparently arisen with respect to the characters of certain Cornish apatites, it may be well in the interests of scientific exactitude to point out the following facts. —In a series of specimens of Franeolite from Fowey Consols one may observe every gradation of form betwixt long and coarsely striated hexagonal prisms and narrow-edged crystals of an almost lenticular shape. Similar to the latter in their small vertical measurement are the "thin hexagonal plates" which have been enumerated among the known varieties of Cornish apatite, and which are, indeed, indistinguishable in general characters from the recently described Francolite of Levant Mine, St. Just. The particular Francolite, however, which, obtained by Mr. Talling from Fowey Consols, was shown by Maskelyne and Flight to contain over 5 per cent. of calcium carbonate (Journ. Chem. Soc. Jan. 1871), must not be identified with any one of the three varieties just mentioned.

Certain specimens of rock lately obtained by me from the "Single Rose" Clay Work, near St. Austell, Cornwall, examples of which are now submitted to the Society, illustrate well the processes by which, in some instances at least, granite has been transformed into an aggregate of quartz and schorl.

A comparison of the chemical composition of orthoclase from Roche with that of kaolin from the neighbouring district of St. Stephen's shows that in the passage of felspar into China clay there is approximately a loss of 26 per cent. SiO2 and a gain of 19 per cent. Al2O3 and 12 per cent. H2O.

In the case of many common rock-forming minerals—the felspars, the pyroxenes, the olivines and the micas—it has been shown that the crystals which have existed in rock-masses at great depths exhibit constant and characteristic differences from the crystals of the same mineral, in rocks of identical composition, which have been formed at the surface. It has been proved, moreover, that these differences become mere and more pronounced in proportion to the distance from the surface at which these rocks have originally existed.

Although some of these peculiarities of the crystals of deep-seated rockmasses can be satisfactorily accounted for by the conditions of pressure and slow growth under which they were originally formed, yet there are others—and these by no means the least striking of them, such as the continuous bands of fluid-enclosures, the avanturine structure and schiller, and the chatoyant phenomena—which are clearly not original, but are due to secondary actions.