Page:Rambles on the Golden Coast of New Zealand.djvu/154

120 comfortable reposing place than between a pair of blue blankets under the calico roof. I dropped across Lamborn’s work on Metallurgy stowed away in a corner. From it I made myself acquainted with many descriptions of ores, their various assays and treatment, and I learned something respecting the valuable constituents of silver and lead. To silver miners and prospectors who may not have read this work, or that of Dr Phillips on Mineralogy, I would recommend their perusal. Dr Phillips says that we are not sufficiently advanced in our knowledge of chemical geology to warrant an attempt to form any general theory of the formation of mineral veins. We need not attempt, therefore, to lay down the theory whereby we may condemn or uphold the value of the discovery of Mount Rangitoto at this early stage. But I cannot refrain from noticing that, in respect to its position on the west side of the mountain, and in regard to the other details of colour, structure, and composition of the rocks and the mineral itself, it compares pointedly and exactly with the descriptions given of many of the oldest silver mines in the world. Then, as to the value of the ore, it compares most favourably, assuming Mr Kirkland’s assay to be correct, with the richest of the known mines at the present day. The most remarkable silver mines, we are told by these authorities, are in Frieberg in Saxony, Kongsberg in Norway, and Huantaya in Southern Peru. The largest specimen ever obtained was got in Peru, weighing eight hundredweight. All the silver produced in the United Kingdom is extracted from argentiferous lead, and in the North of England, mines are worked which yielded as low as 1½ ozs. of silver per ton. In the Isle of Man the average is between 50 and 60 ozs. of silver per ton of lead. In Cardiganshire and Montgomeryshire, the average is between 15 and 25 ozs. per ton. In the Kongsberg mines in Norway, where silver was discovered as far back as 1623, the mines are a hundred miles long by fifty miles in breadth. There, we are informed, the iron pyrites was decomposed and gave rise to the formation of hydrated oxide of iron, the presence of which was the first indication of silver in Kongsberg. There, as here, nearly all the ore-bearing hills run north and south. They are irregular in their dimensions, but all preserve a certain degree of parallelism with each other, and the silver is traced, as I have said, for miles on the west side. The largest silver vein in Mexico is 200 ft. in width, but the majority of the veins, we are told, commence at a few inches in thickness and extend sometimes to 6 or 8 ft. The mean average produce of the Mexican mines, as estimated by Dr Phillips, is a little more than 50 ozs. per ton. The average richness throughout Saxony is 60 to 70 ozs. per ton. Though I do not profess to know aught of geology to determine—what, indeed, would be an exceedingly difficult problem even to modern geologists—the relative ages of the rocks on this coast, or to assign their position in the geological series, I feel assured if a geological report were given by some competent person, it would be shown that similar formations and indications exist here to those of most of the silver-bearing countries mentioned. The first great question to determine with regard to this new discovery is, whether these similar veins are thickening still further in the dip, and whether they will become concentrated in one enormous