Otago, or Southern Gold Fields.
The most extensive alluvial diggings in New Zealand are in this district, and they possess peculiarities that distinguish them from most other gold fields. Notwithstanding the large quantities of alluvial gold that has been obtained in Otago, amounting to 2,548,999 oz., the actual mining operations for the extraction of gold from the matrix, have, up to the present time, been comparatively insignificant.
The gold fields may be divided into two districts. In the eastern district of the province the surface is undulating, and without being mountainous, has a general elevation ranging from 1000 to 4000 feet. The prevailing rock in this district is a very soft mica and chlorite schist cut by vertical joints, and traversed by horizontal laminæ of quartz. The undulations of the surface, as a rule, lie in a direction parallel with the east coast, and each ridge appears to consist of a mass of the schist formation that has been tilted along its western boundary, after the deposit of the Brown coal series (Miocene). A succession of trough-shaped valleys are thus passed over in travelling from the east coast into the interior, along the western side of each of which the Brown coal is generally found to dip under very heavy deposits of alluvial gravels.
The leading features of a section through this part of the province are roughly shown in the accompanying diagram. A B C D are the successive valleys, with the intervening ridges, the most easterly of which shows the Brown coal
formation, capped with Dolerite d, as at Saddle hill, and the others represent Maungatua, Roughridge, and the Dunstan ranges, respectively; a Schistose rocks; b Brown coal formation; c Auriferous alluvium.
Besides the quartz in a laminated form, veins of auriferous quartz exist, and, as a rule, are situated along the lines that mark the lines of uplift of the ranges, or in the positions marked by 1 2 and 3 in the above section, and therefore on the west side of each of the ranges. These are not however to be considered as quartz veins, in the sense in which the term is commonly used in Victoria, and cannot be looked on as the only source from which most of the gold in the Otago drifts has been derived.
One of these reefs has been mined at Waipori and yielded an average of one ounce per ton. Other reefs have been recently opened in the western slope of the Dunstan ranges (3 in section), the results already obtained from which promise much higher returns.
No granite or Diorite dykes are known to exist in this eastern district.
In the western, or Wakatipu Lake district, we find a much greater variety of rock formation. The mountains are lofty and abrupt, and are cut into sharp
ridges and peaks, due partly to the unequal manner in which the different kinds of rocks have resisted denudation, but we must also take into account the effect of great dislocations which appear to have affected this district at a late geological period, for we find at considerable altitudes masses of Tertiary Limestone that are unknown at the same elevation in the eastern district. The schist rocks in this western district are less uniformly foliated than we find them in the east. They also afford a much greater variety of minerals, and even become truly crystalline, in some instances, where dyke rocks intersect them, so that the district may be compared to the north-west district of Nelson.
Several quartz reefs have been mined in this district, on the Shotover and Arrow rivers, and much expensive machinery carried into this district, on the Shotover and positions, but these adventures have not proved so successful as was anticipated. However they were commenced at the time the great exodus of diggers took places to the western gold fields, which may account for the reefing capabilities of the country not being better explored. Judging from its geological structure the north-western district of Otago is the most likely part of the province for the occurrence of mineral lodes.
Before leaving the subject of our gold fields, the general mode of the distribution of the alluvial deposits in New Zealand deserves a further description. This subject is important, as most of the mineral wealth, hitherto obtained, has been from this class of deposits, which is generally associated with iron-ore dust or sand, the black sand of the miners, so that these minerals may be considered together. The source of these, like all other sands, is from the disintegration of a parent rock, and together with the other elements of the rock, they constitute what is known as “drift.” Gold drift consists of sand and gravel containing gold, and is formed by the action of running water in streams, or water in motion, as along a sea or lake beach. The same action causes the re-assortment of the materials, so that the heavier particles become separated from the lighter, and it must be borne in mind that no other agent than water in motion can exercise this sorting influence. It is therefore not merely the existence of auriferous rocks at the surface in a district which determines the extent and richness of the alluvial diggings, but we must also take into account the amount of disintegration of these rocks, and also the degree of concentration to which the detritus has been subjected. As might be expected, alluvial gold is found to vary in composition according to the nature of the rock which formed the original matrix; thus in Otago the gold is pure or only alloyed with a little copper; at Whakamarina, silver appears in the proportion of 7 per cent., while on this side of the Strait it contains double that proportion; and in the north, at Auckland, though the alluvial gold does not contain the same proportion of alloy, as that obtained from the reefs, which is a circumstance that has been remarked on all gold fields, still it is less pure, as a general rule, than the gold from the above-mentioned localities.
In the South, the gold is associated on the other hand with platina, zircons and garnets, and in the Nelson province with the rare mineral, Osmiridium. In like manner the iron sand varies in composition. In the neighbourhood of basaltic rocks, as at Dunedin, it contains 75 per cent. of titanite of iron, which is a refractory compound of the oxides of titanium and iron, while in some parts of the interior of Otage the sands consist either of magnetite or lodestone, or of hæmatite, both of which are pure oxides of iron and more valuable as ores. On the West Coast the sand has also the latter character, and it is worthy of remark that, notwithstanding its proximity to volcanic rocks. The well-known Taranaki iron sand, from its containing only 8 per cent. of titanic iron, apparently belongs to the sands derived from the older rocks principally syenites and altered greenstone slates.
The distribution of these sands, according to the size of their particles, is very instructive, the deposits being of two kinds—beach formed and river formed. The former are principally on the West Coast, both gold and iron sand being of very fine grain. The greatest altitude at which any beach gold has been found is about 125 feet above the sea, at Watchman's terrace, north of the Grey river. It is found everywhere from Cape Farewell to Jackson's Bay, the richest deposit being at Okarita, about the centre of the great Westland Bight. The coast line south of this does not favour the deposit of fine gold, having bold rocky shores and headlands. On the sandy beaches of the south and east coasts of Otago auriferous sand again appears, and has been found as far north on the East Coast as the commencement of the shingle formation of the Canterbury Plains.
In the North Island the great iron sand deposits have their maximum at Taranaki, but extend north and south of that place, rarely being found at a greater altitude than ninety to one hundred feet above the present sea level, though small quantities can be found in nearly every stream, except where flowing wholly within marine tertiary rocks. No gold has as yet been found with any of these deposits in the North Island. The river-formed deposits of gold of the interior of the South Island are divided into three groups, according to their position and the manner they are worked. The oldest drifts are deposits at high levels, out of reach of the present drainage system of the country, so that they can only be worked by bringing water to bear upon them by a system of “fluming.” In Otago such terraces have formed the source of the bulk of the alluvial gold obtained from rich diggings of the second class, which are marginal deposits of rivers and streams, or shallow alluvial flats. Gabriel's Gully is one instance of this, as at the Blue Spur, between Gabriel's and Monro's gullies we find a path of the high level older drift that has been tapped and sluiced down the bed of a modern stream which concentrated the gold. The remaining form of alluvial gold is that liberated by streams which are excavating rocky beds, but the amount is very insignificant compared to that obtained in Victoria with this form of mining. The quantity of gold got by shallow sinking on false bottoms in Otago, has naturally led miners to expect that deep leads will be found to rest on the true rock bottom. This subject requires a rigid enquiry into the causes which have operated in producing the surface features of the country.
We see, as previously stated, that in the West Coast district, a stratum of auriferous alluvium is found to slope to the south from the Nelson province, until at Ross it forms a true deep lead, being worked by underground mines that are below the sea level, and are kept dry only by pumping. But the basins in Otago are very different in character, being deep depressions in the rock which have no outlet at the present time, except through rocky gorges. These basins have been, to some extent, moulded in their form by a previous extension of the glaciers, during the great Pleistocene elevation of the New Zealand area; but the depressions being partly occupied by Brown coal and other Tertiary strata, proves that they are of much higher antiquity than that period, and that the original inequalities are due to dislocations. But, at the same time, there is no question that the glaciers have been the most active agents in breaking up the surface rocks, and filling the depressions with the auriferous alluvium. This is especially evident in the western district, where the glaciers are still at work, and where the valleys which they occupied during their previous greater extension have not been filled up, but are now occupied by lakes. We have, in these cases, an opportunity of examining the configuration of the valleys by means of the sounding line, and Plate 19, which is a map and a diagramatic section of the N. W. district of Otago, between the Wakatipu lake and the West Coast, will assist in making clear the nature of
these lake basins, and the relation of the interior lakes to the Sounds on the West Coast.
The section, the general position of which is shown on the map by the dotted line A to B, has been carried over a higher range of mountains than actually occurs in this line, for the purpose of showing the manner in which the glaciers have excavated the valleys, and rather represents a former than the present condition of that particular part of the range. The dark patches on the map represent a few only of the moraines that are shown on the original map which is in the Otago Museum, and which gives the full details of the Pleistocene geology of this interesting district.
The Wakatipu lake, which is fifty-two miles in length and two to three miles in width, lies, in its upper part, between the Schistose rocks on the east, and the upper Palæozoic rocks on the west, so that it marks the junction of two formations. Its surface is 1070 feet above the sea level, which is exceeded by its depth, for it has been found by soundings to vary from 1170 to 1296 feet, the bottom of the lake being nearly level from side to side, and from end to end. The waters of the lake, at the present time, escape over a rocky fall at Frankton, which is almost the middle of its eastern side, but from the lower end of the lake, at Kingston, a broad valley can be traced to the south, joining that of the Mataura river, which, at first sight, appears to have been the former outlet. The lake is fringed by terraces showing the gradual shrinking of its area, as the level of its outfall has been lowered. The only apparent barriers, in the direction of the Mataura valley, is a great moraine accumulation at Kingston, elevated 270 feet above the level of the lake; but on following down the Mataura river it is found to run over a rocky channel, and to cut its way through a gorge at an altitude of 700 feet above the sea, so that even were the Kingston barrier removed, the lake would not be completely drained in that direction. The lake is therefore contained in a rock basin, and not formed by the simple damming up of a valley.
On the western side of the range, within a distance of thirty to forty miles, we have, on the other hand, a series of arms of the sea occupying exactly similar excavations, frequently 1800 feet beneath the sea level. McKerrow lake is an example of one of these, the exit of which has been barred by coast drift covering a moraine like that barring the lower end of the Wakatipu lake, at Kingston. The outlet of McKerrow lake is by the Kaduku river, which is a tidal river, so that the surface of the lake is at the sea level; yet its waters, which are quite fresh, have a depth of at least 470 feet. Milford Sound, which is also shown on the map, twelve miles further south, has a depth, at its upper part, of 1270 feet, but across its entrance the depth is only 130 feet, while the mountains surrounding it rise to 6000 and 9000 feet.
All the valleys on both slopes of the range are occupied by glacier moraines, and although it is only in the higher cluster of mountains that we now find glaciers to exist, there is no want of evidence of their former greater extension.
The section will explain the operation of glaciers in excavating valleys: a a represents an area of the mountain top, which is above the altitude of perpetual congelation, and from which therefore the snow deposited can only escape by assuming the form of ice, descending by its weight as a glacier b through the valleys to the point at which it melts, owing to the increased temperature counterbalancing the supply of ice. At this point it deposits its moraine or rubbish heaps c, and moraines found further down the valleys are sure indications of the glacier having had formerly a greater extent. At the point where the ice descends from the plateau a to the glacier b, it is generally an abrupt fall, known as the “ice cascade,” and it is at this point that the chief amount of erosion takes place, by which the valleys are eaten back into
the plateau in the lines of least resistance, so that the plateau is at last cut up into sharp ridges and peaks, on which snow can no longer rest in quantity to maintain the glaciers, which consequently disappear, leaving only the moraines to mark the successive steps of the process. This is however quite insufficient to explain the origin of the deep excavations in the hard rock, as above described, and the difference in the amount of the excavation on the opposite sides of the axis, irrespective of the character of the rock excavated, (which is in fact the most resisting in its character on that side where the excavation has been apparently the deepest) points to an unequal subsidence as the origin of these basins. This subsidence has been most rapid in the central and western part of the range, so that in the case of a long valley, like that occupied by the Wakaitpu lake, the slope became gradually reversed, and what was at first the higher part of a glacier-exacavated valley, has become a depression without an outlet. Gradually this depression is being filled up, by the material brought down by the streams, and carried from the moraines higher up the valleys, as represented by d in the section; but this material cannot, especially where resting on the rocky floor of the valley, have been subjected to the action of running water after it has been deposited in the still waters of the lake, and therefore fails in one of the essential processes for the formation of auriferous leads, namely, the concentration of the gold from the lighter particles of the detritus.
From these considerations it is evident that it is only round the margins of rock basins, or in positions above the level of the notch in the margin over which the water escapes, that we can expect to find auriferous leads.
High on the eastern slopes of the mountains, in the position marked e on the section, are found patches of gravels belonging to the newer system which drained the mountain range previous to this unequal subsidence, and before the excavated of the deep gorges by the extended glaciers of the Pleistocene period; and the gold in most of the alluvial workings in Otago, can be traced to such patches of older drift.
I will now describe briefly the mines which have been worked in New Zealand for the less precious metals, and mention the localities where “lodes” have been discovered.
The Island of Kawan, where the earliest opened mine is situated, was first purchased by the North British Investment Company, about 1841, as a cattle run. It lies four miles from the main land, thirty-seven miles north of Auckland, is about three and a half, by three and a quarter miles in extent, and, from the Admiralty survey, appears to have an extent of about 5200 acres. The island consists of slate rocks which form two principal masses of high land, separated by an E. and W. depression, partly occupied by Bon Accord harbour, and continued eastward by several valleys with wide alluvial bottoms. In each of these masses hills rise from 500 feet to 600 feet altitude, the summits marking the outcrop of mineral veins in most cases. The strike of the older rocks is very varied in direction, but ranges between N. E. and N. W. The dip has a prevailing westerly direction, generally at a high angle. All these rocks are, however, cut by cleavage veins and faults, that give them a false trend to N. 320° E. In this line lie the mineral lodes, and “belts” of mineralized rock, four of which are known.
The first discovery was made at Manganese Point, where the lode shows as follows:—
Soft decomposing slate.
Red jasparoid slate, encircled with iron and manganese.
Soft red rock containing the same ores.
From the beds b. and c. a quantity of ore was excavated and shipped to London, where it was sold for £7 per ton.
Within a few months a copper lode was accidentally found cropping out, a large sample of which, taken at random, realized £15 to £20 per ton. This led to regular mining operations, and in 1846 a well-defined lode of copper ore was opened up, twelve feet in width, running N. E. and S. W., with a dip or underlay, of three feet to the fathom. The ore consisted of blue and yellow sulphurets, containing an average of twelve per cent. of copper. Several shipments of the ore were made, in the raw state, but had to be abandoned on account of the danger of fire, from the heat generated by the decomposition which the ore underwent in the holds of the vessels.
Works were then erected for the reduction of the crude ore to the state of regulus, by roasting, in which condition it was a safe article for shipment.
The situation of the smelting works, which were most expensively constructed, was in Bon Accord harbour, where there is deep water close to the wharves.
The first four years workings realized upwards of £60,000, but the pumping machinery was deficient, so that the mine had to be abandoned for eighteen months, till a large Cornish engine was obtained. This effectually kept the water down, and the mine was extended to a vertical depth of 35 fathoms, with a horizontal extent of 150 fathoms, on a lode averaging 6 feet in width, and consisting of a massive gangue that contained thirty per cent. of copper ore, and the same of iron ore, intermixed with dark green chloritic clay. The lode lies between green slates, containing grains of metallic copper, and stained with salts of copper, and a hanging wall of indurated chert.
The mine appears neyer to have been worked out, but was abandoned, partly owing to complications respecting the proprietorship, but mainly owing to the superior attractions of the Californian and Australian gold fields at that time. The particular lode that was worked is on a headland on the south side of the island. It was lost in tracing it inland, to the north, but there is good reason to believe that this headland is only a dislocated mass, formed more in the manner of a landslip than a structural fault, and that there may have been a displacement of the lode. *
The Great Barrier Island, on which have been the most extensive copper mining works in New Zealand, is about twenty-four miles long. A central chain runs through the island, throwing off spurs on either side, rising to an extreme elevation of 2330 feet, and maintaining an average height of about a thousand feet throughout its length.
The greater part of the island is composed of volcanic (Trachytic) rocks, resting on sub-metamorphic slates and sandstones, of the same kind as at, Kawau. These slaty rocks are, in several places, but especially at Mine Bay, cut by intrusive dykes of quartz porphyry, consisting of a felspathic paste containing grains of fine quartz. Felstone, which may be considered as the same rock devoid of quartz, Diorite, which is a mixture of Felspar and the fusible mineral Hornblende, and lastly, a true dyke granite, containing quartz, Mica and Felspar. In these rocks we have representations of the crystalline metamorphic formations, which are so abundant in the South Island, brought to the surface as dykes.
Captain Hutton thus describes the position of mines [Geological Reports, 1869, p. 4]:—
“Some of the dykes of Diorite and Felstone contain, near Mine Bay,
[Footnote] * See “Geological Reports, 1869,” p. 45, for map, and description of Kawau, by author.
copper pyrites, peacock copper, blue and green carbonates of copper, black oxide of copper, native copper, galena, Dufrénoysite and iron pyrites, but not in large quantities.
“The lode which has been worked for copper for some time at Mine Bay, and which now goes by the name of the “Otea Company's Copper Mine,’ is an old fissure in the slate rocks, filled up with angular debris of slate and diorite of all sizes, from that of a walnut or less, to blocks weighing more than a ton. These blocks are cemented together by a matrix that is sometimes siliceous, and at others felspathic, and it is in this cement or matrix that the copper ore occurs. No lead is found in this lode.
“The fissure runs in a nearly north and south direction across the neck of the small peninsula called Miner's Head. This neck is about 200 yards across. The lode is about 25 feet in breadth at the adit level, which is only a few feet above the sea, and expands to about 40 feet at 14 fathoms above adit, and this breadth it keeps pretty regularly until it reaches the top of the hill in which it is situated, and which I estimate to be about 200 feet above adit. I was informed by one of the miners who helped to sink the shaft, that at 12 fathoms below adit the lode was only 9 feet through; it is therefore probable that the fissure dies out altogether at about 20 fathoms below adit. It is, of course, possible that this fissure may be continued downwards indefinitely; but there is no evidence of a fault or slide having taken place, and the facts of its original gaping character, and its constantly decreasing breadth as it gets deeper, incline me to the opinion that it is merely a superficial crack. The fact of the lode containing blocks of diorite shows that the dykes were in existence before the fissure was formed, and that therefore they are not the cause of the lode being charged with copper.”
The mine was first worked in 1845, by Messrs. Abercrombie and Sydney; the ore being a bright yellow sulphide, containing fifteen to sixteen per cent. of metallic copper. The first proprietors worked it for several years, and were then succeeded by Messrs. Whittaker and Heale; then by Messrs. Ninnis and Rowe; and lastly by the Great Barrier Company. The works were then suspended, in 1861, but in 1867 they were again reopened by the Otea Copper Mining Company.
The total quantity of ore mined has been 2,323 tons, the aggregate sales realizing upwards of £30,000. In order to get this ore, Captain Hutton estimates that about 3200 cubic fathoms of vein-stuff have been excavated, which would give a yield of nearly three-quarters of a ton of ore to the cubic fathom; and that about 3800 cubic fathoms remain to be got above the present adit, which will probably yield 2900 tons of ore dressed to fifteen per cent. If my opinion as to the lode dying out about twenty fathoms below adit be correct, it will follow that not more than 4000 cubic fathoms can be got in this direction, which would yield about 3000 tons of ore, making a total of about 5900 tons of ore still remaining in the mine.
Copper ore was also discovered at Whangapara, in a more northerly locality of the same island, but no regular mine was opened there.
Nine miles north of Mongonui, in the promontory that forms the northern boundary of Doubtless Bay, copper was discovered, and partly worked, by Mr. Brodie, about the year 1849.
The peninsula consists, in great part, of porphyritic Trachyte, and Diorite slates. At the copper mine the cliffs are 300 feet high, and the few confined bays at their base are almost inaccessible.
Here a mass of Breccia Conglomerate abuts against a dyke of hard black Diorite. The Breccia consists of a chloritic matrix, with carbonite of lime, and contains large blocks of Trachyte, and quartz Porphyry. Interspersed are masses of sulphide of iron and copper, and also pure metallic copper. “Cop-
per-green,” from the decomposition of these, forms a broad green mark on the cliffs, which first attracted attention from the sea.
The next copper mining adventure to be mentioned is that of the Dun Mountain Mining Company, and for the collection of some of the information concerning it I am indebted to my late assistant, Mr. T. R. Hacket, who came to New Zealand, originally, as Mining Manager to that Company.
Along the east side of Blind Bay, extending S. W. from D'Urville Island, is a line of bare brown hills, which are characterised by low scrubby vegetation, that contrasts with the surrounding green of the forests. These mark what is known as the “Mineral belt,” and their singular barren appearance is due to the large proportion of Magnesia which is mixed with the soil that is derived from the rocks which compose them.
The section of the hills between Nelson and the Mineral range, shows that these magnesian rocks occur in the upper part of the Triassic formation, —the lower part consisting of slates, limestones, and indurated sandstones, containing Triassic fossils, passing, in an ascending series, to Diabase rock and Breccia, associated with Diorite and other dykes. In this part of the formation, metallic ores of copper and chrome occur, not as distinct lodes, but as lenticular masses and nests. Dun Mountain, which is the best known locality, is composed of a peculiar mineral, named Dunite by Professor Hochstetter, which has the same composition as Olivine, a mineral generally found in basaltic lavas. This rock appears at the surface as a large mass, several miles in extent. It is speckled with chromic iron, very much in the same manner as garnets occur in schistose rocks; but the principal deposit of ore is in a band of Serpentine, lying to the east of the Dunite, and between it and a band of limestones. The Serpentine is traversed by dykes of Felstone the Diallage, and a great variety of other minerals—the district being certainly the most interesting locality in New Zealand to a mineralogist.
Copper, associated with Specular iron, was first discovered in 1853, and occurs in the metallic form, and form, and also a red, gray, and blue oxide, but in small quantities, about thirty tons only having been excavated.
The chrome ore forms wedge-shaped masses in the Serpentine, which vary in thickness, from a few inches to as much as twelve feet. The ore is crystalline in its texture, generally pure, but occasionally traversed by thin streaks of Serpentine. The veins are generally discovered cropping out at the surface for a few fathoms in parallel lines, but never form continuous lodes.
Chromic iron which is chiefly used for making dye stuffs, contains about forty-five per cent of chromium, and was worth, before the discovery of the Analine dyes, £10 10s. per ton. 5000 tons have been raised, and the veins already opened expose an estimated quantity of 10,000 tons. The mines, which are at an altitude of 2500 feet above the sea, have been connected with the Port of Nelson by a line of railway 12 ½ miles in length, and having a gradient in a great part of its course, of one in eighteen. The shipments of the ore amount to 4500 tons, which are delivered in London at a cost of £23 13s. per ton.
On the same belt of mineral ground as the Dnn Mountain, several other mines have been opened, in a line extending for fifteen miles, but ore has only been shipped from three of these mines, which possess the same general character as the Dun Mountain mine, without however, the occurrence of the Dunite or some of the other minerals, which might otherwise have been supposed to be necessary accompaniments of the metallic ores. I may mention that the only other place in New Zealand where Dunite has been discovered, besides the Dun Mountain, is at Milford Sound, where it also contains chromic iron, and passes into jade or Maori greenstone.
At Anniseed Valley mine, a few miles south of the Dun Mountain, which
was discovered in 1861, the chrome ore is in serpentinous schists, between a mass of Elvenite with copper, on the west, and a band of limestone on the east; while Black Reef, and Ben Nevis mine, still further south, occur in tough green serpentine. All the mines would yield a large supply of the chrome ore, if there was any demand for it, but they are very difficult of access.
At the northern termination of the mineral belt, a few small copper veins have been discovered, at Croixelles Harbour, and D'Urville Island, the ore, as at Dun Mountain, occurring in small nests in Serpentine and Hornblende schist.
There are two more copper lodes to be noticed, but neither of which have yet been worked. They are both in the Province of Otago, and the ore is Sulphide of Copper, occurring in the metamorphic schists. This first is at Moke Creek, near the Wakatipu Lake, where the lode is about four feet in width. Limestone and wood are found in the neighbourhood, and by reducing the ore to a regulus, containing sixty per cent. of the metal instead of twenty, which is the average of the crude ore, it might be worked with advantage if the land carriage were improved, notwithstanding its distance from the coast.
The second lode, at Waipori, near Tuapeka, has only been imperfectly explored, but it appears to be similar to that at Moke Creek. I will only enumerate a few of the indications which have been observed elsewhere of the occurrence of other ores, as no other mineral lodes have been explored besides those I have mentioned. Thus we have silver lead ore in the Wangapeka river in Nelson; red copper ore in Bligh Sound, on the West Coast, and Magnetic iron ore of Otago; and lastly, I must not omit to mention the Manganese veins which have been worked in the island of Pakihi, near Auckland, an account of the geology of which is given by Captain Hutton in the first volume of our Transactions; nor the rich lode of the same ore which is found at Tikiora at the Bay of Islands.