Art. XLIII.—Geological Notes on the Kermadec Group
[Read before the Auckland Institute, 14th November, 1887.]
Having lately had an opportunity of visiting Sunday and the other islands of the Kermadec Group, I think it may prove interesting to the members of this Institute to learn a little of their geology, as far as the notes I have will allow me to supply it. It is of some little importance to place on record what is known about the islands geologically, in connection with some ideas that have been given forth to the world as to their flora and the relation it bears to the origin of our own here in New Zealand.
Mr. Cheeseman's notes on the collection he made of the flora will prove of great interest, especially as bearing on questions relating to our own and that of adjacent lands. Into this subject, of course, I do not enter, any more than to illustrate it by notes of the geological history of the group as far as it can be ascertained.
The Kermadec Group is one of the latest additions to the British possessions, and it has a special interest for us, inasmuch as it was annexed to this colony on the 17th August last at the time of the Stella's visit, by hoisting the British flag and by formally reading the Governor's proclamation. The group is a very small one, and, but for its position and the great fertility of the soil on the largest of the islands, would be of little value. With the exception, however, of the Chatham Islands it is the most valuable of the several groups of oceanic islands belonging to the Colony.
Sunday, the principal island, is situated just 600 sea miles north-east from Auckland; a little to the east of the route to Tonga, and a little to the west of the route to Rarotonga. A line drawn from Sunday Island, situated in latitude 28° 15 South and longitude 177° 52′ West, in a south-south-west direction for 142 sea miles, would strike L'Esperance, a bare rock forming the most southern isle of the group; and close to this line, at 68 miles from Sunday Island, is situated Macaulay Island, and 22 miles from the latter are the Curtis Islands. These fine islands, with a few islets and rocks off Sunday Island, comprise the whole group, which has a total area of 8,200 acres; Sunday Island absorbing by far the largest portion of this, viz., 7,260 acres.
Captain Sever, commanding the transport Lady Penrhyn, discovered Macaulay and Curtis Islands on the 31st May, 1788. Admiral D'Entrecasteaux discovered L'Esperance on the 16th March, 1793; and Sunday, or, as he called it, Raoul Island, on
the 18th March, 1793. D'Entrecasteaux also gave the general name to the group, calling it Kermadec, after the commander of his consort. The name Sunday was given to it by Mr. Raven, commanding the transport Britannia, who passed it in 1796 on his way from Norfolk Island to Cape Horn. He was not aware of its previous discovery by D'Entrecasteaux. The first settlers took up their residence on Sunday Island in 1837, and from that time to the present it has been occupied by various parties of settlers, none of whom, however, ever stayed there any length of time, owing principally to causes which I shall refer to in the geological description.
Situated in latitude 29° 15′ South, the climate is mild and equable, although in winter high winds are of common occurrence. The insular character, doubtless, tempers the heat which might be expected from the latitude. We found the temperature, during our ten days' stay in August last, very pleasant, and slightly higher than that of northern New Zealand.
The islands are wholly of volcanic origin, and are, geologically speaking, of recent date. I have attempted to show, in the case of the Bay of Plenty volcanic district, that all the extinct volcanoes there found, as well as the active ones, including Tarawera and also the points of greatest thermal activity, follow a line drawn from Ruapehu to White Island, which, there is every reason to believe, denotes one of those great fissures of the earth so characteristic of volcanic districts. This linear arrangement of volcanoes is so marked a feature as to render it unnecessary to point out the many countries which illustrate it. In the Kermadec Group, further evidence of the ruling process by which volcanoes are built up along linear fissures is afforded. If we study a map of the Southern Pacific, we shall find that, by prolonging the volcanic axis of the Bay of Plenty, it will strike through this group, and, if continued still further in the same general direction, that Tonga and Samoa will be seen to be in the same line. At both of these places volcanic activity is still to be found, but more especially at the former, where two notable eruptions have occurred within the last few years—viz., that on the Culibras Reef, on the 11th October, 1885, and that at Niuafou in August, 1886.
This line appears to mark the centre of a region of elevation, separated from similar ones on either side by oceans of abysmal depths. Unfortunately, the soundings between the coasts of New Zealand and Tonga are few and far between. The Challenger, one of whose special duties was that of deep-sea sounding, only obtained four between the places named—i.e., one off the East Cape, of 700 fathoms; two between Sunday and Macaulay Islands, one 40 miles north of the former; and one of 2,900 fathoms between Sunday Island and Tonga, but 150 miles
to the east of a line drawn between those places, and, therefore, off the plateau. A few other soundings have been obtained along this central line by other ships, and these, together with some shoals and reefs lying between the Kermadec and Tonga Groups, all go to prove that the plateau is probably continuous in this direction. Many rocks, reefs, and shoals have been reported from time to time as lying south-westerly from the Kermadec Group, but there are doubts about them all. Her Majesty's ships have frequently searched for them in vain; and it is believed that those who reported them were deceived by the colouring of the water due to the presence of Mollusca.
Although the region under consideration may be called an oceanic plateau, the depth of water on it is very great—deeper probably than the height of most of our northern mountains; and, therefore, when we find little islands like the Kermadecs appearing above the sea, we readily conceive them to be the tops of mountains rising to great heights above their bases. We are happily in possession of a most excellent survey of Sunday Island and the neighbouring seas, made by Captain Denham, of H.M.S. Herald, in 1854. From his chart we find that this island stands on a plateau, the waters on which are of moderate though uneven depth. At one mile from the shores the mean depth is about 350 feet, though in one place within half-a-mile of Nash Point it is as much as 1,290 feet. There can be little doubt that this moderate depth—which is somewhat unexpected from the abruptness of the coast-line—is due to the erosion and destruction of the former extensions of the island, the materials of which have been spread over the sea bottom in its vicinity. In the neighbourhood of Macaulay, Curtis, and L'Ésperance Islands, we find from Captain Fairchild's soundings that the waters are also comparatively shallow for about a mile off the coasts. As, however, we pass away from the land, between Sunday and Macaulay Islands, a depth of 3,120 feet and 3,780 feet was found by the Challenger; whilst 40 miles to the north of the former the depth is 3,600 feet. Sunday Island, being 1,723 feet high, it follows that it is a mountain standing on a broad base, with an elevation of 5,300 feet.
The islands are all, in fact, the tops of volcanic mountains appearing above the sea; and I believe they originated in the eruption of matter from the great fissure I have indicated as probably extending from Ruapehu to Samoa, and which passes through this group.
With regard to the age of the islands, there is very little to guide us in forming an opinion; but bearing in mind Sir James Hector's statement, to the effect that the volcanic activity which caused the elevation of the central plateau of the North Island of New Zealand commenced in Eocene times, we are led to infer that the Kermadec volcanoes will be of about the same age. It
would be at that time, in all probability, that the great fissure, or fracture in the earth's surface, was first formed, or re-opened, and a period of great volcanic activity set in, which has continued in a decreasing degree to the present time.
The islands being wholly volcanic, we cannot expect the assistance of fossils in determining their age. It seems unlikely that any such should be found so near volcanic rents; but I wish to mention—more as a hint to future visitors than anything else—that Mr. Bell told me he had found a fossil kukuroroa, or great mussel of New Zealand, embedded in a mass of pumiceous tuff which had fallen from the cliffs on the east coast of Sunday Island. The finding was related with such circumstantiality that I can scarce doubt the fact, though I searched half a day in the locality without seeing anything of it.
In stating that the islands date from Eocene times, it should be understood that this was the age when the volcanic forces first commenced to build up on the sea bottom the mountains we now see. Their present shapes are due to much later movements: indeed, some of the surface indications go to prove that alterations have taken place in comparatively quite recent times. Doubtless the first outburst must have been submarine, and ages would elapse before the mountains appeared above the sea-level.
On Sunday Island—which is somewhat triangular in shape and about 20 miles in circumference—we can trace a great deal of the method by which it has been built up. All round the island, except on the north side, can be seen very distinctly a series of lava flows, composed of black and dark-brown andesitic rock, all of which lie nearly horizontally. Separating these flows in a great number of places are bands of red laterite, varying from a few inches up to several feet in width. These bands are interesting as proving that the outbursts of lava were intermittent, and that a sufficient time elapsed between each for land surfaces to form and vegetation to flourish, to be destroyed by the following overflow, and by it to be converted into the laterite we now see. On the northern side the lava flows are hidden by later deposits, which have extended outside them. The rents from which these horizontal lava streams exuded are lost. They probably originated when the island was of larger extent, for I do not think they emanated from the craters whose remains can still be seen. Resting on top of these lavas, somewhat irregularly, are beds of pumiceous tuff of great depth, which are composed principally of a dark coloured pumice, fragments of andesite, obsidian, and other rocks. It is difficult to say whether the whole of these tuffs are the product of the existing craters, but I think not; they are more likely to have been deposited previously to the formation of the craters, which have since burst through them.
There are two distinct craters to be seen on the island, besides a smaller one of quite recent date, and probably a third one existed, the remains of which are to be traced in the Herald Islets, the lava flows and pumiceous tuffs of which all have a uniform dip in a direction differing from that of the great crater itself. The oldest of these is only in part remaining. The almost perpendicular cliffs of Denham Bay form half of the old encircling rim, the other half having been washed away by the action of the sea; but even here the volcanic forces are not yet extinct: there are still a few fumaroles on the eastern side, at the foot of the cliffs, sending forth a little steam; and not more than fifteen years ago the old crater showed signs of somewhat remarkable activity, of which I have obtained the following evidence.
The first settlers lived on the flat in Denham Bay; they left in 1847, being frightened by the earthquakes and signs of a coming eruption. The next settler, Mr. Cook, of the Bay of Islands, left in 1853, being also frightened away by an expected eruption. In 1872 occurred the eruption in the other great crater, to be referred to later on, and at this same date also occurred an eruption in the Denham Bay crater. As the people then living there escaped in a whaler at the first sign of the outburst, we have no very definite particulars, but this much is certain, that an island was thrown up in Denham Bay, of size sufficient to form a shelter to vessels anchoring under its lee. It was landed on by Captain Hoosier, one of the whaling captains, and by Reed, lately an officer of the notorious Petrel, and was described by them as being formed of sand and stones, quite hot to the feet. Mr. Cook, who was there again in 1877, describes it as a “mountain of sand;” but at the date of his visit it had become a shoal. Lord George Campbell, an officer of the Challenger, heard from the whalers at Tonga, in 1874, that an island had been thrown up southwest of the group, doubtless referring to this; and further evidence of it is to be found in the presence of the Wolverine rock, or shoal, on which there is only 1 ½ fathoms of water, and over which the sea breaks heavily even in ordinary weather. This rock was certainly not in existence when Captain Denham made his exhaustive and excellent survey in 1854, or he could not have failed to see it. Cook also mentions that the lagoon on the flat had “been exhausted” (i.e., dried up) when he was there in 1877. At the present time the only signs of activity are a few fumaroles at the base of the cliff, and which lie in a direct line between Denham Bay crater and the great crater of Sunday Island. The walls of this old crater are most distinctly seen in Denham Bay to be built up of successive lava flows, capped by the pumiceous tuffs on top; and so steep are they, that access to the summit is only to be found
in one place where a rugged footway has been formed by the settlers.
Lying immediately to the east of the crater I have described, and separated from it by a narrow ridge, varying from about 800 to 1,500 feet in height, is the great crater of Sunday Island. This has a length of 1 ¾ miles, with a breadth of 1 ¼ miles from rim to rim, and is, taken altogether, a very perfect specimen of its kind. The internal slope of its sides is exceedingly steep, indeed in many places it is quite inaccessible where not covered with vegetation. The peak called Moumoukai, on its eastern side, is 1,723 feet above sea-level; and as the lake in the bottom is but 40 feet above the sea, it will be seen that the crater is of great depth. On the north side, however, the encircling rim is much lower; one point, in a gap or break in the ridge, being only 180 feet above sea-level. At the present time the sides are generally covered with vegetation, though here and there are bare places, causedby the destruction of the trees during the eruption in 1872.
The crater lake in the bottom is fresh water, and just one-third of a mile in diameter, and nearly circular in shape. Captain Denham's chart shows two little islets in it, but these are now submerged, and only the dead tree-tops are to be seen appearing above the water. The chart also shows a smaller lake, about a quarter of a mile to the south of the other one, and this at that time was surrounded by a ring of hills of no great elevation, denoting a crater rim. It was in this little crater that the eruption of 1872 took place, and which drove away the then inhabitants of the island—a man named Covat, who, with his family, escaped in a whaler to Fiji. When we come to consider the size and depth of this great crater, it will be seen how much material has been removed by that all-powerful agent steam. If I am right in supposing the horizontal lava flows, seen in the cliffs of the island, to be more ancient than either of the craters to which reference has been made, it follows that these solid beds have been removed altogether, and have been scattered in fragments far and wide, whilst much of the pumiceous matter ejected has also disappeared by the gradual washing away of the shores of the island. In the fertile flats on the north coast of the island, elevated 200 feet above the sea, we find part of the remains of this ejected matter, which must at one time have extended far beyond its present bounds. These flats are formed of horizontal beds of pumice, andesitic and obsidian fragments, all of which are easily acted on by the waves and the weather. No lava streams can be traced as originating from the crater; but in more than one place on the north and east coast of the islands there are dykes of very large size formed of andesite, and these appear to have been forced through the pumiceous tuffs. They are of somewhat different composition to the horizontal augiteandesite lava flows described.
In Meyer Island there are several such dykes to be seen, but they are here very much smaller, more regular, and stand up above the surface like broken walls; they are also andesitie in composition.
After the great crater had ceased its activity, the smaller one within it, which is shown on Denham's chart, appears to have been formed on its bottom. The chart of 1854 shows this as a small circular lake within a ring of hills. From all the information I have been enabled to gather, there was no sign of activity displayed at the time of Captain Denham's survey. The great crater bottom was at that time, and for long after, covered with pohutukawa and nikau palms; and the soil has been described as of very great richness. The little crater had apparently died out and become extinct.
Sterndale, who passed some days on Sunday Island in 1869, makes no mention of volcanic or thermal action as then to be seen, and so observant a man would certainly have done so had there been any sign of such; but in September, 1872, he visited the place again, and then says: “In the early part of 1872, the water in the little freshwater lake on Sunday Island began to boil furiously, which was followed by a column of fire spouting up from the middle of it. A whale ship in the neighbourhood, seeing the flame, bore up, and took off Covat and his family…. In September, 1872, I landed there…. I found no one, and the place was much scorched towards the interior. All signs of volcanic disturbance had disappeared, with the exception of the dead trees on the hill-sides surrounding the little lake, and some black cinders and ashes which were strewn about the margin.”
The island was without permanent inhabitants until 1878, when Mr. Bell took up his residence there, so that we have no record as to whether there was any eruption subsequent to that of 1872. Our fellow-townsman, Dr. Stockwell, spent three days on the island in October, 1876, and he tells me that the larger lake was at that time of quite a different shape to what it is shown on Denham's chart, and to what it is now. It had then somewhat of a serpentine shape, the banks were covered with mud, and altogether it was of smaller size than at present. A little vegetation was seen on the southern walls of the great crater; but in a direct line from the little crater, (or as it is now called, the Green Lake), towards Bell's homestead, there was no sign of vegetation, nothing but bare consolidated mud and fragments of rock. This belt was about a quarter of a mile wide. The walls of the great crater, on the east and north-east sides, had not been affected by the mud thrown out so copiously, but in the other parts there was a good deal of it scattered about. At the present time this belt of mud is so thickly covered with vegetation that nearly all signs of the eruption have disappeared.
It is far different, however, at the bottom of the great crater in the neighbourhood of the Green Lake. When the outburst took place, the mass of ejected mud, pumice, and rock broke away the encircling ring of hills, and poured down into the larger lake, partly filling it, and for a time raised its waters some 10 feet higher than it is at present, as may plainly be seen by the blocks of pumice stranded some way back from its margin. At the same time a great mass of mud and fragments of rock were ejected in all directions from the little crater, destroying the vegetation, some of it falling on the southern side of the greater crater within which the Green Lake lies, and there, in its descent, bringing down all the trees, and leaving the cliffs bare, as they still are in some places at the present day. The depth of this deposit is about 12 feet around the rim of the crater, and through it are protruding the stumps of the pohutukawa trees killed at the time of the outburst. The last material to be ejected from the crater was pumice, in blocks of all sizes from an inch to 2 feet in diameter; and this was apparently not cast out with sufficient force to overtop the crater rim, for it is confined to a level bed rising about 10 feet above the level of the water, and surrounds the lake as a raised beach. Amongst the matter ejected are quite a number of vomited masses of molten andesite, very like pitch-stone in appearance, as large as small oranges. At the present time steam at a temperature of 135° escapes from two or three places within the crater rim, but no hot-water is found. There is a somewhat singular cave on the east side, from the floor of which the steam arises in sufficient quantities to make it unpleasantly warm, and on the sides of which is deposited a considerable amount of soft white matter not unlike gypsum.
It is remarkable that there was a considerable falling-off in the volume of steam from these places in the week following the Tarawera eruption, as observed by the Bell family. Mr. Bell assured me that the place is now not nearly so active as it was prior to June, 1886, and this fact affords further evidence of the connection between New Zealand and Tonga, along the fissure I have attempted to describe.
The land surrounding the Green Lake presents a very desolate appearance, covered as it is with hard mud, pumice, obsidian, and fragments of andesite; but the pohutukawa and Kermadec ngaio are gradually gaining a hold on it, and in a few years' time will have obliterated all signs of the eruption. It is noticeable that the stumps of the trees still protruding above the mud are nowhere of any size, thus probably indicating that the eruption of 1872 was not the first one in that locality which was sufficiently serious to destroy the vegetation.
Although the eruption of 1872 is the latest which has occurred on Sunday Island, a disturbance of much more recent date took
place in its neighbourhood. Mr. Bell informed me that in March, 1886, (just three months before the Tarawera eruption), he left the island in the whaler Othello, Captain Earle, for New Zealand. When 5 miles north of Sunday Island, they sailed for some time through a great mass of floating pumice, which was estimated to be 3 miles long by 1 ½ in width. This was observed to be rising up from the bottom and spreading out from the centre of the mass. Evidently this was a submarine eruption, though no steam or other evidence of it was observed.
The only signs of volcanic activity at present observable on Sunday Island are those I have mentioned—viz., a few small fumaroles in Denham Bay, some equally insignificant escapes of steam from the Green Lake crater, and an outflow of hot-water below high water-mark on the northern beach. The whole island is covered with a dense vegetation of trees and ferns, excepting in the immediate neighbourhood of the Green Lake.
At 68 miles S.S.W. from Sunday Island is Macaulay Island, which is roughly circular in shape, and about a mile and a third in diameter.
The highest point is at the western end, where a rounded hill, 781 feet in height, with steep nearly perpendicular cliffs on the seaside, marks the position of an old volcano. The island is surrounded on all sides by perpendicular cliffs, varying in height from 200 to 500 feet, and the surface is covered with a smooth sward of grass. These cliffs afford a means of studying its structure much better than in the case of Sunday Island. It is clearly seen to be the remains of a volcanic mountain, the western half of which has disappeared by denudation. The old neck or throat of the volcano is still to be traced in the solid lava of the western cliffs, from whence the various beds that form the island slope away to the east in regular series. The lowest seen is a hard andesitic lava, which forms the base at the sea-level all round the island, and which has flowed from the volcano at the west end. Above it comes a deep bed of light-coloured pumiceous tuff, full of blocks of pumice, obsidian, and fragments of andesite for a depth of about 200 feet. This bed of pumice, etc., was the last ejected from the old volcano. Subsequently—but after what space of time no one can tell—a change took place in the locus of activity. Another and much smaller crater was formed on the east side of the old one, the outline of which is still quite distinct though it is imperfect in shape, the eastern side having been nearly all carried away. The matter first ejected from it was a series of andesitic lava flows, of no great extent, which spread out in different directions as they rolled down the slopes of the older mountain, following in several instances the pre-existing gullies, and in one case falling over the edge of the pumiceous cliff underneath in a lava cascade, which now forms the only accessible ascent to the top
of the island from the beach below. In other cases the lava streams are seen to fill up crevasses and hollows in the underlying pumice, conforming to the undulations of its surface. This lava appears to have been in a very liquid form, for it is nowhere more than a few feet thick, and has run along slopes which have a very gentle inclination. Following the lava was an ejection of black and dark-brown vesicular scoria, very much like in outward appearance that seen in any of the cones around Auckland, but differing somewhat from it. The presence of olivine crystals in it shows, however, that the scoria is basaltic. The scoria is deposited much deeper around the little crater from which it emanated, and thins off from there towards the eastern and lower parts of the island, being perhaps 100 feet deep near the crater, and 2 to 4 feet on the lower ground. Finally, following the scoria, an eruption of mud or fine ash of a dark-brown colour took place, and this forms the not unfertile soil of the island; it is about 4 feet deep.
To the east of Macaulay Island, and separated from it by a narrow passage is Haszard Islet, which is formed of the same lava and tuff as the larger island, but the scoria has not extended so far. But here the inclination of the beds is in the opposite direction, denoting that a partial subsidence has taken place along the line occupied by the passage, which is probably a fault. Viewed from any direction, Macaulay Island presents a pleasant appearance; the gentle undulations of the surface, covered as they are with a close sward of green grass, would form an attractive feature to the agriculturist were the island situated near our own coast. Landing on its rock-bound shores is very difficult, except in one place, and with favourable weather, under the shelter of Haszard Islet, where a little sandy bay is found.
It is doubtful whether there is permanent water to be found; we saw none but a little in some rocky pools, and that was after a recent heavy rain.
Twenty-two miles south of Macaulay Island are the Curtis Islands, separated from one another by a deep channel a quarter of a mile wide.
The eastern island is much the largest and most interesting of the two, for here we have a crater much more active than those on the other islands; though this is in what is called the solfatara stage. The island appears to be formed of massive lava, standing up out of the sea in perpendicular or overhanging cliffs for a height of 500 feet. The crater is situated on the north side, and is formed by a deep hollow in the massive rocks, with almost perpendicular sides all round, excepting on the north, where the sea enters by a little cove, the only landing-place on the island. The floor of the crater is about 15 feet above the sea-level, and scattered over its surface are a number
of solfataras, fumaroles, boiling mud holes, and heaps of sulphurous mud. A strong stream of very hot water runs out of the crater into the cove, the salt waters of which are warmed by it for some distance from the shore. There is a considerable amount of activity displayed by the numerous fumaroles, the steam rising, perhaps, a hundred feet from some of them, with the usual accompaniment of noise so common in the Rotorua District. Many of the boiling mud-holes are of considerable size, and their contents are seething and twirling about, just as, we see those at Tikitere, at Rotorua, and other places in that district. Our visit to the crater was so very brief that I was unable to procure any rock specimens, all our attention having been given to exploring the crater, and viewing the various fumaroles. We had intended to make a complete examination of the island on the following morning, but bad weather coming on we were obliged to leave without doing so. I regret this the more, as I believe the rocks are not formed of the same andesite common to Sunday and Macaulay Islands; they have more the appearance of trachytic rocks from a distance. As we passed round the island, steam was observed to be escaping from several places in small quantities from the outside cliffs. Curtis Island is a mere crater rim, or chimney top, standing up above the sealevel, and on which scarcely any vegetation is to be seen. It has somewhat the same features as White Island, in the Bay of Plenty, but is on a smaller scale.
The last island of the group is L'Esperance, or French, or Brind, Rock. It is situated 52 miles southerly from Curtis Islands, and is—as its name suggests—a mere rock standing in the solitary waste of waters. It is, like the others, of igneous origin, but as we were unable to land I cannot say what the rocks are composed of. The height is about 230 feet, and length 280 yards. A somewhat remarkable feature in it is a crater-like or cavernous hollow on the eastern side. The rocks of which it is composed look like the augite-andesite lavas of Sunday Island; but there are two distinct kinds, the second being a reddish scoriaceous one, which appears as if it had been ejected from the crater-like hollow, and had subsequently become consolidated and bound together by some cementing matter. There is a little vegetation on the rock, apparently the ice-plant common on the larger islands.
It will thus be seen, from the imperfect description I have given of the group, that nothing but igneous rocks are met with, and that these (with one exception) belong to the basic, or, rather, the transition from the acidic to the basic, class of volcanic ejecta. The exception is a rock found on Sunday Island as boulders, on the north and east sides, which the miscroscope shows to be syenite, one of the plutonic rocks. Its presence can only be explained by the supposition that it
has been brought up from great depths by volcanic agency, just as has been the case at Tarawera. It is only found in smooth rounded boulders on the beach, and then in no great quantities; but still there is enough to preclude the idea that these have been brought there by the hand of man.
With the exception of this syenite, the islands afford no support to the theory that a continent, now submerged, extended formerly in this direction, and on to the other islands of the Pacific—at any rate within the more recent geological periods—and by which means our fauna and flora travelled down from the north. If ever such land connection existed, it must have been in very ancient times, probably long before the dawn of the Tertiary period. The solution of the problem as to how the present flora and fauna of the islands became domiciled there must be left to other hands than mine to deal with; I will merely point out that the presence of kauri logs which can be traced to our northern rivers, together with all the facts we know with respect to the currents between there and New Zealand, suggest some thoughts as to their origin that are worthy of attentive study.
In conclusion, I beg to tender my sincere thanks to our President, Professor Thomas, for the great trouble he has taken in the microscopical examination and naming of the rock specimens brought from the Kermadec Islands.