438 PROCEEDINGS OP SECTION C. 



10.— THE PHYSIOGRAPHY OF PORT NICHOLSON 

 HARBOR, NEW ZEALAND. 



by JAMES MACKINTOSH BELL, Director of the Geological Survey of ls!ew 



Zealand. 



[With Map.] 



The harbor of Port Nicholson, on which Welhngton, the capital of 

 New Zealand, is situated, forms a prominent indentation in the southern 

 coastline of the North Island. The harbor is a fine sheet of water, 

 almost landlocked, about nine miles long by five miles wide, connected 

 with the open water of Cook's Strait by a narrow channel of water about 

 one and a half miles long and about one mile in width. The harbor is 

 almost completely surrounded by high hills, which rise, in general, very 

 abruptly from the water's edge. There are, however, several fair-sized 

 areas and many small patches of level or gradually .sloping land close to 

 the edge of the harbor. By far the most extensive of these is that which 

 forms the relatively wide valley of the Hutt River, extending north- 

 eastwards from the north-eastern end of the harbor. This plain has a 

 width of nearly two and a half miles near the harbor, and gradually 

 narrows as it extends inland. 



Westward from the narrow channel, connecting Port Nicholson 

 Harbor with the sea, is a ridge of low rocky hills. West of this ridge 

 of hills lies the area of low-lying country which separates Lyell Bay 

 from Evans Bay, bordered to the westward by the Kilbirnie Hills, which 

 have a maximum altitude at Mount Victoria of 648ft. above sea level. 

 Westward of the Kilbirnie Hills lies another area of comparatively low 

 country, on which is located the city of Wellington, having a slope on 

 the northern side to Lambton Harbor and on the southern side to Island 

 Bay. To the westward of the city of Wellington rise the Karori Hills. 

 The northern continuation of the Karori Hills forms the precipitous 

 country bordering Port Nicholson on the west and north-west and alsa 

 the Hutt Valley further north. There is continuous high country from 

 the entrance of the harbor along its eastern side up the Hutt Valley. 



There are two small islands in Port Nicholson — Ward Island and 

 Somes Island — which are approximately in line with the continuation 

 of the hills lying west of the entrance to the harbor. 



A view from any prominent part of the hills around Port Nicholson 

 discloses an elevated country stretching in all directions, broken by 

 narrow valleys and deep ravines. The most salient feature of the land- 

 scape is the generally uniform elevation to which the hills ascend, 

 namely, between 700ft. and 800ft. This uniform elevation does not 

 represent a plateau, and since it is quite independent of the structure 

 of the country rocks (consisting of tremendously contorted and shattered 

 argillites and grauwackes), it apparently exhibits, somewhat roughly^ 

 an elevated plain of erosion or peneplain. Above the general level of 

 this peneplain a number of hills rise to altitudes of greater prominence, 

 forming apparently residuals from an earlier cycle of erosion than that 

 represented by the peneplain. These may be considered as monadnocks. 



