PROCEEDINGS OF SECTION C. 439 



Since the elevation of the peneplain, the spacious harbor of Port 

 Nicholson has been formed. This has been produced by the down- 

 faulting of an area of country, forming a graben extending from Cook 

 Strait north-eastwards up the valley of the Hutt River. This graben 

 apparently does not represent a single down-faulted block, but consists 

 of several parallel and transverse blocks, not all of which have settled 

 equally, either longitudinally or transversely. Thus it seems evident 

 that the ridge of hills bordering the western side of the entrance to the 

 harbor, with Ward Island and Somes Island, and also the Kilbirnie 

 Hills, represent portions of the peneplain which have sunk but little or 

 not at all ; their reduced elevation, as compared with the general height 

 of the peneplain, being due to the more rapid denudation consequent 

 on their isolated and exposed positions. In the same way, the low- 

 lying areas of country between Lyell Bay and Evans Bay and between 

 Island Bay and Lambton Harbor have apparently not subsided to the 

 same depth as the floor of the main body of the harbor, though it is not 

 improbable that both these areas were either originally below sea level 

 or at least occupied a lower altitude than at present, their height above 

 sea level and general surface area being increased by the advanced of 

 wind-blown sand. As every student of New Zealand geology knows, the 

 harbor of Port Nicholson underwent several comparatively slight 

 changes of level during the past century, and Wellingtonians owe part 

 of the flat land on which their city is built to one of these tectonic 

 movements. 



The plain along the valley of the Hutt River is but little elevated 

 above sea level, and has been formed by the laying down in the graben of 

 material brought down by the rapid-flowing Hutt River. This plain 

 is rapidly advancing into the harbor. 



The time of the maximum down-faulting of the country during 

 which the harbor of Port Nicholson was formed was evidently not 

 geologically remote, as shown by the even and abrupt coastline to the 

 east and north-west of the harbor. These coastlines in general mark 

 the planes of maximum faulting to which the many other planes are 

 subsidiary or parallel. 



The diastrophic history of the area of country in which Port 

 Nicholson Harbor is situated may be briefly summed up as follows : — 

 First were laid down a series of sedimentary rocks, which were uplifted 

 and intricately folded, producing a mountainous country. Gradually, 

 through long periods of time, these mountains were worn down almost 

 to sea level, and a rough peneplain was produced. Then came the 

 elevation of the peneplain, and later the sinking of the graben, which 

 has given the beautiful land-locked harbor of Port Nicholson, on which 

 New Zealand's capital is situated. 



