Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/445

1869.] ULRICH-"NUGGETTY REEF." 335 Magnetic pyrites. Scattered through the quartz in small patches; not found in crystals as yet.

Copper-pyrites. Like the former, but rather more rare.

Galena. Very abundant, finely disseminated, and in patches; but seldom, and always imperfectly, crystallized.

Zinc-blende. Finely disseminated and in small patches, generally in connexion with galena; not yet observed crystallized.

Maldonite, Bismuthi Gold. Generally in the neighbourhood of the granite-veins, and often a few inches deep in the granite itself, specks of a soft malleable ore occur, having a pinkish silver-white colour, with a brilliant metallic lustre when freshly broken, but tarnishing gradually when exposed to the atmosphere, becoming first of a dull copper-colour, and ultimately quite black. Of this rare ore only a very small quantity has yet been available for blowpipe experiments, by which I determined it to be an alloy of bismuth and gold, and for an assay, made by Mr. Cosmo Newbery, which showed its composition to be 64.5 gold and 35.5 bismuth, agreeing closely with the formula Au2 Bi. Being, as a natural product, quite new to science, it is proposed to name this alloy "Maldonite" after the locality of its occurrence. It is softer than pure gold, fuses more easily before the blowpipe on charcoal, and, whilst turning to a bright gold bead, imparts to the chacoal the yellow coating of bismuth. It shows no trace of tellurium, sulphur, &c. Cleavage apparently cubical; very sectile. It is no doubt the ore that gave rise to the frequent admixtures of bismuth in the gold of the Nuggetty Reef.

In addition to the different ores just mentioned, which, with the exception of the "Maldonite," appear to increase in quantity beneath the water-level, there occur frequently in the quartz, and not at all confined to the neighbourhood of the granite-veins, irregular patches and imperfect crystals of bluish and greenish-white felspar (oligoclase) and of silvery white and black mica; also, scattered through the reef, narrow veins and small lumps of a white kaolinic clay.

In conclusion, it may not be out of place to remark that the surface-workings on this interesting reef present a glaring instance of misspent labour and capital, due no doubt to the dislike to cooperation, often noticed among the miners in the early times of the Victorian gold-fields. Running up the steep slope of the hill, called Mount Moorul, the main portion of the reef in strike, and considerably over 100 feet in dip, might easily have been worked by one main shaft, in connexion with a tunnel starting from a deep gully that runs alongside the reef. Instead of this, however, at least a dozen costly shafts have been sunk, out of which the quartz had to be raised by windlass or horsewhim, to be directly shot down again by means of shoots to the bottom of the before-mentioned gully, whence it was carted to the crushing-machines in the neighbourhood.