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porphyry and serpentine. A characteristic feature of the limestone of this zone is the numerous funnel-shaped pits and caves, reminding us of the caves of the Karst Mountains in Austria. The interesting phenomenon of the Waikoromumu Springs in the Takaka Valley, which send forth a powerful gush of water, is explained by the supposition that the water, after a long subterraneous course, breaks suddenly forth. This zone can also be traced in a southerly direction as far as Lake Eotoroa. It is followed by the mica-schist and clay-slate zone. Garnet-bearing mica-schist, alternating with quartzite, constitutes the highest, sharply-serrated crests of the western ranges in the Anatoki Mountains, with peaks reaching a height of 6,000 ft. above the level of the sea, while further to the west the mica-slate passes imperceptibly into clay-slate (phyllite). The Aorere Valley, and the mountains, 4,000 ft. to 5,000 ft. high, on its east side, such as the Slate Eiver Peak, Lead' Hill, Mount Olympus, and the whole of the Haupiri Ranges, belong to the clay-slate zone." There are several slight errors in the above general description of the rocks of this part of the Nelson District, and these have been passed over as of little importance in the present case; but as, in the following report, Slate Eiver Peak, Lead Hill, and Mount Olympus concern us nearly, it becomes necessary to state here that Lead Hill and Mount Olympus are formed of granite, while Slate Eiver Peak and the neighbouring region consists of breccias sandstones and green slates indurated, but unaltered, which, by Mr. Park, are referred to the Devonian period. The more schistose rocks of Silurian age lie to the north-west within the main valley of the Aorere watershed, and in the upper valley of the Aorere Eiver these are interposed between the granite areas of the Leslie Eange and that to the north-east, embracing Mount Olympus and Lead Hill. "The strata are very much inclined, throughout the whole mica-slate and clay-slate zone, and variously bent. On Mount Olympus the strata diverge from below towards the serrated edge of the mountain-top like the folds of a fan. In the, as yet, but little explored Wakamarama coastrange the succession of crystalline slates seems to repeat itself in an inverted order, but with less thickness." Here also it is important to note that considerable areas of unaltered, or comparatively unaltered, Silurian schists are met with in the part of the district lying to the westward of the Aorere Valley. This fact, and the extent of these rocks, will be made clear in a further quotation from Mr. Park's report on the district. Meanwhile, to continue : " While, on the West Coast, granite again appears. The mica-schist and clay-slate zone—which, in a breadth of fifteen to twenty miles, includes principally the Anatoki and Haupiri Eanges, probably continues in a southern direction through the whole chain of the New Zealand Alps —contains in its quartz veins and beds the matrix of the gold. The gradual denudation of the mountains, continued through countless ages, has produced masses of detritus, which were deposited on the declivities of the mountains in the shape of conglomerates, and, in the river-valleys, in the shape of alluvial gravel and sand. In this process of deposition, carried on under the influence of running waters, Nature herself has effected a washing operation, during which the heavier particles of gold contained in the mountain detritus collected themselves at the bottom of the deposits and close to their source, so that they can now be obtained by digging and washing. The conglomerates accumulated on the slopes of the mountains are the proper fields for the ' dry diggings,' while, from the gravel and sand of the beds of rivers and smaller streams, the gold is obtained by 'wet diggings.' The latter were those first worked. Nearly all the rivers and creeks running from the Anatoki and Haupiri Eanges, either east to the Takaka Valley, or west to the Aorere Valley, or, like the Parapara, towards the north into Golden Bay, have been found to be more or less auriferous. "The Aorere diggings are situated partly in the main valley itself, partly in the numerous side valleys intersecting deeply the slate-rock at a distance of from five to twelve miles from Collingwood. The gold is washed from the alluvium of the rivers by sluice-boxes and cradles. It is a scaly gold, with rounded particles, which prove that it has been exposed to the action of running water, and brought thither from a greater or less distance. Yet nearly every valley, and even creek, contains gold of somewhat different appearance. While most of the gold is very pure, that of Slate Eiver, for example, has always a brown ferruginous coat. On the Appos River the gold is accompanied by crystals of iron-pyrites, which remained behind in the process of washing ; in other places magnetic iron, or titaniferous iron, is found in company with gold. The fact that the heaviest gold is found in the upper parts of the streams points clearly to the mountains as the original source of the metal. "But it would be improper to speak of an Aorere goldfield if the gold were confined to the deep and narrow gorges of the streams, cut down into the clay-slate rock. The whole region of the eastern side of the Aorere Valley, rising from the river-bed towards the steep sides of the mountains at an inclination of about B°, and occupying from the Clark River to the south, to the Parapara on the north, a superficial extent of about forty English miles, is a goldfield. Throughout this whole district, on the foot of the range, we find a conglomerate deposited on the top of the slate-rocks, attaining in some places a thickness of 20ft. Pieces of drift-wood changed into brown coal, as well as the partial covering of the conglomerate with Tertiary limestones and sandstones at Washbourne's Flat indicate a probable Tertiary age of this conglomerate formation." This question—viz., the age of the different auriferous gravels in the Aorere Valley—will be discussed further on, but here it is important to note that Hochstetter recognised that some of these underlie the limestones of Tertiary age that are found in the low grounds and along the east side of the Aorere Valley. "Where a ferrugenous cement binds the boulders and the gravel together, this conglomerate is compact, in other places only fine sand lies between the larger stones. Quartz and clay-slate boulders are the most commonly met with. This conglomerate formation is not only cut through by the deep gullies of the larger streams, but in some places washed by the more superficial action of water, and is thus divided into parallel and rounded ridges, of which that portion of the district called the Quartz Ranges is a characteristic example. This conglomerate formation must be regarded as the real goldfield, prepared in a gigantic manner by the hand of Nature from the detritus of the mountains for the more detailed and minute operations of man.