96

With regard to other minerals in the western ranges, there are no indications of quicksilver, as it was supposed. But Mr. Skeet informed me, that pieces of lead ore are found in the Waingaro river; and large masses of brown iron ore, which have been mistaken, from their somewhat similar appearance, for scoria, are deposited at the Parapara. This has given rise to the idea of the Parapara being volcanic.

2.—PRIMARY FORMATIONS IN THE EASTERN RANGES.

The eastern ranges are of an entirely different geological formation to those just described in the west; old primary slates and sandstones, of very various character, form lofty ridges, intersected by parallel longitudinal valleys. The strata are all, more or less, vertical, and the parallelism of their strike from north-east to south-west continues with remarkable regularity. One and the same stratum can be traced from Cook Strait to the far interior in the south.

In the central ridge, which has its northern termination in Mount Stokes, between the waters of the Pelorus and Queen Charlotte Sound, the slates exhibit a more crystalline character. At Ship's Cove and Shakspeare Bay in Queen Charlotte Sound, in the Kaituna Pass, and other places, almost crystalline micaceous clay-slates, with quartz layers and veins, occur.

On either side of this central ridge the slates exhibit a more sedimentary character, alternating with dioritic-schists, with amygdaloids, with very compact sandstones, approaching the character of greywacke. As no fossils have yet been found in those oldest sedimentary New Zealand schists, it is impossible to assign to them their geological place in a European classification of strata.

The slate and sandstone ridges are flanked by serpentine.

Below the confluence of the Blarich river with the Awatere, where the side of the mountain has slipped with an earthquake rent, serpentine appears. The Grey Mare's Tail is a waterfall over a serpentine cliff. The serpentine extends, in a south-westerly direction, through the Blarich valley towards Mount Mowatt, whose south-eastern slope to a height of about 2,000 feet is composed of serpentine. In the bed of the Blarich river, Mr. Haast found a piece of copper ore of the same description as the Dun Mountain ores.

On the western side, the serpentine occurs developed to a much greater extent. An immense serpentine dyke, of a thickness of several miles, stretches from the northern extremity of D'Urville's Island, across the French Pass, through the Croixelles, by the Dun

Mountain, and Upper Wairoa, and is met with again, on a continuation of the same straight line, on the red hills, near the Tophouse. On the northern side of the Wairau valley. This dyke can thus be traced from north-east to south-west for a distance of eighty miles. The strike of the serpentine dyke is perfectly parallel to that of the slates, but its eruptive origin is proved by the occurrence of a breccia of friction (Reibungs breccia) at the line of contact, and the fact of beds of slate enclosed in it being converted into hard and semi-vitrified cherts. The serpentine, in its turn, has been broken through by eruptive dykes of hypersthenite and gabbro. The rock of the Dun Mountain proper is a variety of serpentine, of so novel and peculiar a character, that I am obliged to apply to it a new term, and call it "Dunite." The Dun Mountain district offers to the scientific geologist a field of unbounded interest; but I shall perhaps best respond to the wishes of my audience by telling them something about the ores of copper and chromate of iron, which are the characteristic metals of that serpentine dyke.

COPPER.

The occurrence of native copper, red oxide of copper, and copper pyrites, the principal copper ores of the Dun Mountain, is by no means peculiar to the serpentine of New Zealand. In the serpentine district of Cornwall, for instance, native copper is found. The Monte Ramazzo, near Genoa, contains copper ores in serpentine; and in North America, the same thing occurs.

I have visited (accompanied by Mr. Hacket and Mr. Wrey) all the workings of the Dun Mountain. I could not convince myself of the existence of a number of parallel lodes, so as to justify the various names which have been given, and which appear to designate different lodes. The Dun Mountain copper ore does not occur in a regular lode; by which I mean a metalliferous dyke of different mineral composition from that of the rock of the Mountain. As is usual in serpentine, the copper ore occurs only in nests and bunches. The richer deposits of copper ore form lenticular shaped masses, which, when followed, may increase to a certain distance, but then disappear again in a thin wedge. Where these nests are large and rich, one alone may sometimes make the fortune of a mine. The richest found on the Dun Mountain appears to have been that of the Windtrap Gully, from which pieces of native copper (some of them weighing as much as eight pounds) were extracted. These nests of copper ore occur in the Dun Mountain in one continuous line, as if a rent had taken place in the serpentine rock, into which copper had either been injected from