At Terras mine there is an interesting junction of a well-marked tin-bearing elvan, whose course is about north and south, with a bed of greenstone, whose general bearing is nearly east and west. Near the junction, a few years since, a shaft was sunk 40 fathoms deep for the purpose of working a tin lode which was believed to cross the elvan just refered to at that point. At a depth of about 10 fathoms the bed of greenstone was met with, and it continued for 6 fathoms in depth in a very hard state, but from thence to the bottom of shaft it was much softer.

The rock is one of the hardest and toughest I have ever come across. Ordinarily it is composed of a fine-grained mixture of hornblende and silica, but it contains numerous narrow cavities or partial fissures, which near the shaft in question are often studded over or lined with small crystals of the three arseniates mentioned above.

In looking over some specimens of chalkosiderite in the possession of Capt. Simmonds, of Liskeard, I noticed a bluish green mineral which was different from the rest, and subsequently on calling the attention of Capt. Hosking of West Phoenix to the mineral I obtained several pieces from him.

From a very early period gold has been found and worked for in Scotland. We have records dating as far back as the time of James I., in which grants were made to different parties to search and mine for this metal; and no doubt it was obtained at a much earlier period. The gold ornaments found in Scotland, with other relies of pre-historie times, were doubtless manufactured from native gold. Several localities are mentioned in these old grants where gold was to be searched for; but by far the most important district is that generally mentioned as Crawford Moor, which appears to include the range of hills at Wanloekhead and Leadhills, and the streams which fall into the Clyde on the one side, and those which reach the Nith and Annan on the other. The head water of the Tweed, where gold has been found to a limited extent, appears to have been included in this district.

These constitute interesting objects for the microscope. The first mentioned is calc spar, having perfect rhombohedral cleavage; it is transparent, or translucent, apparently coloured topaz yellow or mnber, by the intimate diffusion of oohreous iron throughout. The distribution of the colouring iron oxide through the carbonate of lime is minutely microscopic, in tangled interlacing curved lines, many of which, if not all of them, are hollow tubes not unlike maccaroni or vermicelli, but, although this form of iron oxide is distributed through the calc spar in such close masses, it does not seem to affect the cleavage planes of the latter, which separate as readily as if no ochreous iron had been present.

This Lamp is shewn half size in figs. 1 to 4. Fig. 1 is a section of the whole lamp ; fig. 2 a view from above ; fig. 3 shews the mode of folding the wick ; and fig. 4 the tinplate cover, which serves as a stand while the lamp is in use.

It is provided with a “bayonet” slot, which works over the little pin shewn in fig. 1, so as to keep the cover in place when it is put on over the lamp.

The body of the lamp is made from a piece of iron or lead gas pipe, 1 1/2in. internal diameter, to one side of which the wick holder is soldered. I find that “night light” grease suits admirably—ordinary composite candies do very well.

In the year 1874 the steamship Faraday whilst engaged in grappling for the broken telegraph cable, caught the strong claws of the grapple in a rock, which resisted with the strain of about 27.5 tons, to which any but a rope of marvellously perfect manufacture would have yielded. As it was, the rock gave way, and a lump of black basalt came up weighing 21 lbs. This mass shewed signs of having been torn off. The fragment, and the section made from it for the microscope which accompanies this memorandum, were submitted to Mr. J. Clifton Ward, who has kindly examined the specimen, and drawn up the report enclosed herewith.

I cannot find in any charts indications of the habitual voyage of icebergs so far eastwards in the same latitude as the spot in question, and I have consulted Dr. John Rae as to the question of the rock being from an ice-borne mass. He says in reply, that he is not aware of icebergs having been seen about that spot, but that such an occurrence is not impossible. He thinks it more likely that, as I had suggested, the fragment was wrenched off some submarine peak or summit or ridge.

The origin of the large deposits of Celestine that abound in certain beds of Triassic age has long been a puzzle to Geologists. At Bristol, Celestine is found only on the lowest beds of the Keuper marls resting on the solid red sandstone rock, and may be collected by the ton.

It occurs in large masses, in veins and in geodes, accompanied by Selenite. In many of the concretions the crystals are long and acicular, radiating from the centre. In other places they seem to be a simple aggregation of crystals so loosely bound together that they may be easily rubbed asunder by the slightest pressure of the fingers. The most beautiful forms, however, are those in the interior of the geodes. They are very large tabular prisms with the angles, edges and planes clearly defined. Their colour is white with a delicate bluish tint, and tolerably transparent, having a diameter frequently as much as an inch.

The Mineral from West Phoenix occurs in globular masses of a Turquoise blue or bluish green color upon Limonite. The interior of each spherule is composed of Limonite within which is sometimes a minute quartz crystal; the exterior surface usually shews indistinct crystalline facets. Fragments examined with a hand-lens shew a conchoidal fracture, but a thin section exhibits faint indications of radiated and concentric structure.

The first specimen which came under my notice was given to me by Mr. Simmonds of Liskeard, in October 1875 as a variety of Chalcosiderite or Andrewsite. These minerals had recently been described by Professor N. S. Maskelyne and Dr. Flight, and as there is occasionally a certain resemblance between them and the new mineral, and they all occur together, it was supposed to be the same as one of them. As the specimen was small I placed it in my cabinet, being unwilling to destroy it by making an analysis.