when the land stood at a higher level. We find the series of sounds and inlets on the south side of the strait, Queen Charlotte Sound, Pelorus Sound, ^* etc., with a depth of from ten to thirty fathoms. These sounds must have been originally excavated by fresh water, and what are now arms of the sea must have been river valleys. A rise in the level of 200 feet would again convert them into valleys.

The deepest sounding in Cook Strait that I can find on the chart is 178 fathoms. Therefore a rise in the land of 1100 feet would shut out the sea, and lay the strait dry. Let us consider what the effect of this would be, supposing the rise to be uniform over the whole plateau. The highest point of the newly-reclaimed land would be between Cape Farewell and Taranaki, where the soundings vary from thirty-three to fifty fathoms. The run of water would therefore be from there towards the south-east, reaching the present sixty fathoms off D'Urville Island, and eighty-four fathoms off Kapiti. In the narrow part of the strait the depth is greater than on either side. This may be caused either by a convulsion of nature, or, by what is just as probable, the scour of the narrow channel being deposited outside, probably to the eastward. In the narrows there appears to be an irregular bottom from 100 to 178 fathoms, while between Cape Campbell and Cape Palliser there is a depth of ninety-nine fathoms. It is clear that, on the before named supposition, the great Cook Strait River must have run to the eastward. If we consider the extent of its tributaries, we must suppose a very large river.

Say on the north we commence with the Patea river. We have next the Waitotara, the Whanganui, the Wangaehu, the Turakina, the Rangitikei, the Manawatu, the Otaki, the Hutt, the Ruamahunga. On the south we should have all the streams flowing from Massacre Bay, Tasman Gulf, the sounds of Pelorus and Queen Charlotte, and the Wairau river.

Suppose we carry the argument still further, and imagine a general rise of the New Zealand plateau to the point of emergence, so that we should join on the Chatham and Campbell Islands. What rise might be required I do not know, for I am not aware that soundings have been taken. In that case we may imagine our great river flowing to the eastward to be joined by the Canterbury and Marlborough rivers, from the Waitaki to the Clarence, probably all converging into one.

The two systems combined would form a river worthy of a large continent.

I would suggest that there are other means of causing a rise or fall of the sea level than the movement up or down of the solid.

At the time when a large part of Europe emerged from the ocean, a corresponding quantity of water must have been displaced. It is by no means

unreasonable to suppose that this may have passed to the southern hemisphere, and drowned out some of the southern lands. It is conceivable that at one time in the southern hemisphere there was breadth of land from east to west, as well as length from north to south, while in the northern hemisphere, at the same period, the conditions may have been reversed. Possibly this theory may give a clue to the date at which the great Cook Strait River existed.

But, apart from such a speculation, let us consider the effect of local causes. The west coast of the North Island, broken through by the lavas of Mount Egmont and other volcanos, has evidently been an area of depression. This involves the converse proposition, viz., that at one time it was an area of elevation, and we may suppose that the elevation extended across the strait and joined the two islands.

We may suppose that before the deposition of the tertiary rocks there was a period of elevation of the older rocks, followed by periods of depression, during which the tertiaries were deposited. This was probably succeeded by a period of elevation, during which the tertiaries emerged to a greater extent than at present; followed again by a period of depression during the time when the volcanos of Mount Egmont and Ruapehu were in a state of activity.

It may be fair to infer that it was during the latter period of elevation that the Cook Strait River existed. We may picture to ourselves at that period a similar condition to that of the rivers of Canterbury—an upper valley system within the present limits of the strait, the emergence of the river from a gorge in the narrows between Wellington Head (Tory Channel) and Terawiti, and a further course through the plains to the eastward. Whether these plains extended beyond the present sixty or seventy fathom plateau, or were continued for a long way to the eastward, is a point for future research. It is possible that the investigations of H.M.S. Challenger may tend to throw the amount of light on the subject which may be gathered from a study of soundings and of the configuration of the sea bottom.

The arguments for the former existence of a Cook Strait River may be concisely recapitulated as follows:—

• slight, is from the westward to the eastward. It is hardly possible that this could be the case had not the land to the westward formerly stood higher than that to the eastward. Therefore, although the land in the vicinity of Wellington was much higher than at present, that to the westward was higher still.

Having thus, I trust, proved the existence of a former Cook Strait River, I am tempted, in tracing the outlet of the fresh-water lake of Port Nicholson—to which we may perhaps give the Maori name of the harbour, viz., Whanganuiatera—to picture the magnificent fall over which the waters of the outlet rushed before joining the main river. This fall was probably at no great distance from Lyall Bay, although, as the trend of the outlet may have been to the eastward until perhaps it was joined by the Ruamahunga, besides smaller streams, and taking a more gradual slope to its final goal it may have avoided violent action, the question of the waterfall may be considered speculative and involved in some doubt, as although the fall to the main river must have been considerable, it may have been sloped off in a series of rapids by the course of the river trending to the eastward.

We have in this province, and at the present day, an illustration of the possible opening of a strait by the action of a river. The Manawatu, rising in the Forty-Mile Bush, on the eastern side of the main range, breaks through that range at the Gorge, and has cut for itself a channel which does not now stand at much above 400 feet from high-water mark. Consequently a depression of the district to the extent of 500 feet would enable the waters of the ocean to pass through the Gorge into the Forty-Mile Bush, and a little more depression would bring these waters into the valleys of the Wairarapa and Whareama, thus forming a channel with two branches, and converting the peninsula of Wellington Province into two islands. I suppose the water would, at the same time, pass northward through the Ruataniwha plains to Napier, and insulate the southern part of the Province of Hawke Bay.

It appears to me, also, that the present configuration of the sea bottom would probably involve the former existence of a large lake or lakes in that part of Cook Strait lying to the westward, through which lakes the great river flowed. I think I have shown that there was every reason to suppose that formerly a great river flowed through Cook Strait, and that its course was towards the east.

Some further Proofs as to the ancient Cook Strait River, and the Harbour of Wellington as a Fresh-water Lake; also, a Consideration of the Date at which the Islands were united.

[Read before the Wellington Philosophical Society, 10th February, 1875.]

On reading my papers on the above subjects at the meetings of the Wellington Philosophical Society during the last two years, I was asked for my

proofs in the way of fresh-water shells, or other evidence, to show the presence of fresh water. Now, if the movement of the land had been upwards instead of downwards, had the harbour or the strait been laid dry instead of being covered with the waters of the sea, no doubt, supposing the theory to be correct, plenty of evidence would have been forthcoming. But, as the movement has been in a downward direction, it is sufficiently obvious that the evidence required is difficult, perhaps impossible, to be found, and that although we have such evidence as the remains of terrestrial plants far below the present surface, yet, to prove the point satisfactorily, we must apply circumstantial evidence and other processes of reasoning.

I think it must be admitted by any one who gives the subject a very small consideration that the two chief islands of New Zealand were at one time united. The flora of both islands is almost identical, the differences mainly consisting in what might reasonably be expected from difference of latitude, and consequently of temperature—absence of frost in the north, and its presence in the south. Thus the magnificent kauri tree and the valuable puriri are not found to the southward of Taranaki, but the tree-ferns and the nikau palm thrive from one end of the islands to the other, along with the mass of forest trees and plants common to both islands. From the evidence of the flora of the islands we may make sure that they were at one time connected.

But the evidence is far stronger when we consider the fauna of New Zealand. From north to south we have the wingless or non-flying birds, the kiwi and the weka. We have the remains of the moa, and other birds wanting in flight, in great quantities in both islands. It is simply out of the question to suppose that these birds spread from the North Cape to Foveaux Strait in any other manner than by land, and for this purpose it will be necessary that we admit the islands to have been joined.

Now, the only way in which the islands could have been united must have been by a former higher level of the land in Cook Strait. This being granted the rest of the argument is incontrovertible. Suppose the bottom of Cook Strait to rise so as to unite the islands, then a river is at once required for the drainage of the reclaimed land, and the required rise would convert Wellington harbour into a lake. There is no alternative.

That the supposed river ran from the westward to the eastward there is every reason to suppose, because the slope of the bottom of the strait is in that direction, and because the ranges between Terawiti and Queen Charlotte Sound have been breached and a wide channel formed.

The argument now leads further, and points to the time at which the islands were joined. This must have been during the period of the existence of the moa and other non-flying birds, and therefore, geologically speaking, at