Park. — Changes of Const-level. 443 



well-known raised beach around Wellington Harbour was 

 upheaved suddenly during an earthquake about forty years 

 ago, and must not be confused with the evidences of slow 

 secular movement. 



The raised terraces on the coast-line of Canterbury and 

 Otago, and the recent excavation of the narrow rocky gorges of 

 the Clutha, Taieri, and other rivers draining the east side of 

 the " great divide," point to a slow but continuous elevation 

 of the land which may still be in progress. On the other 

 hand, there can be little doubt that the fiords or sounds of 

 south-west Otago were narrow mountain-glens excavated by 

 subaerial agencies at a time when the land stood at a higher 

 level than at present. The subsidence which has been in pro- 

 gress in that region since post-Tertiary times has allowed the 

 sea to run up and fill the submerged glens. Thus each fiord 

 will mark the site of a submerged valley. 



New Zealand, from its insular position, its division by the 

 sea into islands, its numerous harbours and extensive coast- 

 line, is destined to become an important maritime nation. It 

 will always be dependent on the sea for its communications 

 and commerce, both internal and foreign, and this will neces- 

 sitate the erection and maintenance of harbours, docks, and 

 coast-protection works of a costly and permanent character, 

 specially adapted to accommodate the trading-vessels of the 

 future. It is quite certain that, in the design and erection of 

 these works, the direction of the secular movements of the 

 land will be factors demanding serious consideration. Hence it 

 is now our duty — a duty we owe to posterity — to erect around 

 our shores permanent marks or stones, the positions of which 

 have been accurately determined, for the guidance of the engi- 

 neers of the future. For example, an accurately determined 

 progressive and uniform upheaval of the floor of a harbour at 

 the rate of, say, 6 ft. in a century would necessitate the intro- 

 duction of important modifications in the design of dock- 

 accommodation intended to be of a permanent character. 

 Further, it is well known that subsidence in an area allows 

 the accumulation of silts, sand, and gravels in the estuaries, 

 harbours, or rivers in that area ; while, conversely, the rising 

 of an area permits the sweeping-away and scouring-out of 

 old accumulations of alluvial detritus in harbours and similar 

 situations. Since the engineer is called upon to combat, or at 

 least direct, the forces of nature, he should be provided with a 

 full knowledge of the direction of these forces, otherwise his 

 best-devised schemes may soon become useless, if not actually 

 destructive. 



Stone marks have long since been erected on their shores 

 by most of the civilised maritime states of Europe and 

 America, and the time has arrived when this should be done 



