been under water for years, in many parts of the world, formations of iron and silica have been found on the walls and roof, while in mining tunnels which have been long unused stalactites composed of silica and calcite have formed.  Then, again, experiments made by the late Professor Cosmo Newbery, in Victoria, showed that a distinctly appreciable amount of gold, iron, and silica (the latter in granular form) could be extracted from solid mine timber; which had been submerged for a considerable time.

This reaction then must be in progress at the present time, and doubtless under certain conditions pyrites would eventually take the place of the timber, as is the case with some of the long buried driftwood found in Victorian deep leads.  Again, we know that the water from some copper mines is so charged with copper sulphate that if scrap iron be thrown into it, the iron will be taken up by the sulphuric acid, and metallic copper deposited in its place.  All this tends to prove that the deposition of metals from their salts, though probably not now as rapid as formerly, is still ceaselessly going on in some place or another where the necessary conditions are favourable.

With regard to auriferous pyritic lodes, it does not appear even now to be clear, as some scientists assert, that their gold is never found in chemical combination with the sulphides of the base metals.  On the contrary, I think much of the evidence points in the other direction.

I have long been of opinion that it is really so held in many of the ferro-sulphides and arsenio-ferro sulphides.  On this subject Mr. T. Atherton contributed a short article in 1891 to the Australian Mining Standard which is worthy of notice.  He says, referring to an occurrence of a Natural Sulphide of Gold:  “The existence of gold, in the form of a natural sulphide in conjunction with pyrites, has often been advanced theoretically, as a possible occurrence; but up to the present time has, I believe, never been established as an actual fact.  During my investigation on the ore of the Deep Creek mines, Nambucca, New South Wales, I have found in them what I believe to be gold existing as a natural sulphide.  The lode is a large irregular one of pure arsenical pyrites carrying, in addition to gold and silver, nickel and cobalt.  It exists in a felsite dyke immediately on the coast.  Surrounding it on all sides are micaceous schists, and in the neighbourhood about half a mile distant is a large granite hill about 800 feet high.  In the lode and its walls are large quantities of pyro-phyllite, and in some parts of the mine there are deposits of pure white translucent mica, but in the ore itself it is a yellow or pale olive green, and is never absent from the pyrites.

“From the first I was much struck with the exceedingly fine state of division in which the gold existed in the ore.  After roasting and very carefully grinding down in an agate mortar, I have never been able to get any pieces of gold exceeding one-thousandth of an inch in diameter, and the greater quantity is very much finer than this.  Careful dissolving of the pyrites and gangue so as to leave the gold intact failed to find it in any larger diameter.  As this was a very unusual experience in investigations on many other kinds of pyrites, I was led further into the matter.