666 Transactions. — Geology. 



of ConifercB, though differing somewhat from the kauri (Dam- 

 mara australis), project in a semi-carbonised state, proving 

 that at a comparatively short time before they were still era- 

 bedded in the seams of lignite. 



Within the Hokianga Eiver, also, the same destructive pro- 

 cess is m operation, and 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, so far from the sea encroaching, the land is actu- 

 ally 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 tlie 

 west coast of the North Island, so far as I iiave had an oppor- 

 tunity 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 scien- 

 tist it only remains to take facts as w'e 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 in- 

 creased 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 de- 

 posited 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 Eangaunu estuary, and extending up to- 

 wards the old mission-station of Kaitaia, were at no very dis- 

 tant 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 por- 

 tions of the trunks and roots of mangroves still in situ. 



It seems probable that as time goes on most of the pre- 

 sent extensive mud-flats in this locality will gradually become 

 covered with silt, and eventually be rendered fit for cultiva- 

 tion. Within the last thirty years much land formerly useless 

 on account of being covered by the tides, has now become suf- 

 ficiently 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 



