marked on the west coast. They consist of apparent encroachments of the sea on the land, and a gradual eating-away of those portions of the coast-line which, not being protected by dykes of hard rocks or banks of drifted sand, are exposed to the wash of the tides. In many places that I can call to mind between the Manukau Heads and the North Cape this process of denudation is going on at an active rate.

In the Manukau Harbour extensive stretches of mud-flats exist, with stumps of trees, some of them of great size, still showing, though in most cases they have been eaten level with the surface by the Teredo navalis.

In the Whangape Harbour in particular, within the memory of men still resident there, many acres of once-cultivated land have been swept away, and nothing is now left but bare mudflats, showing here and there the stumps of some of the larger manuka or other woods sufficiently deeply embedded in the subsoil to resist the ravages of the waves for a time at least. So persistent is the attack of the sea that the Natives have been compelled to protect the face exposed to the waves with breastworks of split timber, in order to save some of their most fertile kumara plantations from totally disappearing.

These facts seem to indicate that at some previous period most of these mud-flats were low-lying stretches of alluvial land, covered with forest, which have been encroached upon by the wash of tides gradually rising higher, and the vegetation destroyed by the salt water, until finally nothing was left but the present stretches of mud-flat, bare for miles at low water.

The coast-line from Kaipara Heads to Maunganui Bluff, many miles in length, shows very distinctly that the sea has made inroads on the solid land, or, in other words, the land projected much further into the ocean at one time than it does at present.

The coast-line is remarkably straight, and, as the formation is similar throughout, the erosive action must be very regular along the whole line.

The general appearance of the coast is a very flat, hard beach, with very little shifting sand, extending to the base of soft sandstone cliffs ranging from 60ft. to 100ft. in height. During high spring tides, with westerly winds or westerly gales generally, the seas beat against the foot of the cliffs and wash out the softer seams of sandstone, when, the face being undermined, large masses break off and come tumbling down on the beach to be speedily swept away by the breakers.

Exposed in the face of the cliffs are seams of lignite, one above the other, ranging from a few inches to several feet in thickness. This substance appears to be of recent origin, for in places huge trunks of trees belonging to the natural order

of Coniferœ, though differing somewhat from the kauri (Dammara australis), project in a semi-carbonised state, proving that at a comparatively short time before they were still embedded in the seams of lignite.

Within the Hokianga River, also, the same destructive process is in operation, arid wherever the sea comes in contact with those places where the soil is not composed of stiff clay or rock-bound, its ravages are only too evident.

On the east coast a different state of things prevails. A close examination of different points along the coast-line gives one the impression that high-water mark has receded of late years, and, go far from the sea encroaching, the land is actually making along the whole eastern coast north of Auckland.

A casual remark by the captain of a coasting steamer, who has been trading on the coast for years, that “the harbours on the east coast are shallowing perceptibly,” in addition to what I had observed on the west coast, led me to devote some thought to the subject, for, if correct, the inference is that the west coast of the North Island, so far as I have had an opportunity of observing it, is gradually subsiding, and the east coast becoming correspondingly elevated.

There may be scientific and. satisfactory reasons for these interesting phenomena, but until explained to us by a scientist it only remains to take facts as we find them.

The captain's theory to account for the decrease in depth of the harbours he is in the habit of visiting was that the increased cultivation in the interior, and destruction of the forests beneath the axe of the settler, caused a larger quantity of silt than formerly to be brought down in freshets, and deposited on the anchorages; but, as the same causes do not apparently operate on the west coast, it seems to point to the weakness of the explanation.

It seems to be fairly well established that the low lands surrounding the Rangaunu estuary, and extending up to-, wards the old mission-station of Kaitaia, were at no very distant period covered with salt water, as settlers, while sinking wells on the Kaitaia and Awanui flats, have penetrated at a greater or less depth into solidified mangrove mud, with portions of the trunks and roots of mangroves still in situ.

It seems probable that as time goes on most of the present extensive mud-flats in this locality will gradually become covered with silt, and eventually be rendered fit for cultivation. Within the last thirty years much land formerly useless on account of being covered by the tides, has now become sufficiently elevated above the water-level to be available for cultivation, and is being utilised for that purpose. At more than one place-notably at Te Mahia, between Gisborne and Napier–the natives have traditions that at one time the sea