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the tide just there runs stronger than anywhere else inside the lake.

It will be seen by reference to the charts, that the ebb and flow of the tide is from south to north, and from north to south in the bay, and that its greatest force is felt just where the mouth of the lake now is; and that so long as the tide ebbs and flows in that direction, so long will a great force of water press upon the sand spit, forming the lake, at about that particular spot; and as the rate of the flow of the tide through the entrance is from 6½ to 7 knots, it is clear that the action of the flood and ebb tides upon the entrance must be something like that of a force pump, the rush of water being so tremendously strong; and I have no doubt that that force may be used to any extent, for the purpose of opening new channels and of keeping open old ones.

Secondly. The Ahuriri Roadstead and Entrance to Port Napier, illustrated to a scale of 10 chains to 1 inch on Chart No. 2.

The Rangitira sand-bank, which is the particular feature of this harbour entrance, is subject to great changes, shifting its position under the influence of heavy gales of wind. It has been known to extend right across the entrance, so as to render the passage of vessels exceedingly dangerous; but its general position I believe to be about where it is marked on the chart.

The rise and fall of the tide ranges from three feet four inches to three feet seven inches; ordinary springs from four feet to four feet four inches; occasional high spring tides produce a rise of four feet six inches. The highest tides recorded by Mr. Murray (to whom I am indebted for these figures) is four feet eight inches, the rate of flow being as before stated, from 6½ to 7 knots per hour at the narrowest part of the entrance.

It will appear by comparing the chart now submitted to you, made by myself, with that made by Mr. Park in 1850 and with that made by Captain Drury of H.M.S.S. Pandora in 1855, that the entrance to Port Napier is undergoing great and rapid changes: for, according to the charts made by those gentlemen, the width of the entrance was in their time from 6 to 7 chains: now, according to the chart made by me, it is 13 chains, having increased to twice its width in 15 years—a very rapid change indeed. The depth of water is materially affected by this change in the width of its passage; for whereas by Capt. Drury’s soundings the greatest depth was 5 fathoms in 1855, now I find in 1865 the greatest depth to be four fathoms, from which data it would seem that as the entrance to the lake widens, so also does it shallow, and that the quantity of water is not affected by the increase or diminution of the width of that passage, from which significant fact some very important conclusions may be arrived at affecting the contemplated harbour improvements.

The direction of the ebb tide rushing out of the harbour was, about a month ago, due North, but it is subject to deflections according to the position of the bar or the Rangitira Bank.

The “Iron Pot” appears to have been formed by a tidal eddy and to be maintained alone by that cause, and I am inclined to think that any interference with that natural condition of things must result in its filling up so as to be useless for shipping purposes. It is evident from the table of soundings (as per margin)* taken in 1862 and 1865, that since the commencement of what are called the “Harbour Improvements” a very great change for the worse has taken place in this interesting locality; at all events it can only be maintained in a useful state at an enormous first and an annual expenditure.

The shoals just inside the entrance shift under the influence of high floods and heavy seas, but return to their normal position upon the subsidence of the disturbing cause.

Thirdly. The rivers flowing through the Ahuriri Plains and into the Lake.

The Native chiefs, owners of the Ahuriri Plains, strongly opposed my taking levels over that line of country, upon the ground that, somehow or other, that operation was connected with the introduction of steamers into their rivers. Mr. Commissioner Cooper was present at the time of these objections being made, and to him I referred the matter, but that gentleman did not appear able to make any impression upon the objectors in favour of the levels.

I have, however, taken some few levels and measurements, from which you will gather that the fall of the Ahuriri Plains is from West to East, and that from North to South or South to North there is no material inclination, at all events not sufficient to overcome the natural tendency of the rivers flowing through the lower part of the Plains to flow into the sea at due East from their sources, except in the case of the Tutaekuri river, if after all exception may fairly be taken to that river, which for the last two miles of its course runs from South to North, upon which line the fall is slightly more than between the point of its deflection and the sea, going East.

A section line drawn from Pakowai to Mr. Rhodes’ flats will show that the bottom of the Ngaruroro River at Pakowai, is very much lower than that of the Tuki Tuki on Rhodes’ flats; in fact, it is some feet below high water mark at Awapuni, for by measurement I find that the North bank of that river at Pakowai is 18 feet above low water mark, and that the depth of water below that again is about 9 feet, and that the rise and fall of tide is about 2 feet.

Iron Pot. { 1862—11 feet to 12 feet } Deepest
{ 1865—9 feet to 10 feet }