538 Transactio7is. 



Similarly, too, tlie wearing-action of the waves has probably increased to 

 some extent the area of the harbour, and undoubtedly modified its bound- 

 iiries. - 



The plain along the lower Hutt Valley is but little elevated above sea- 

 level, and has been formed by the laying-down in the original faulted or 

 river-modified depression of material brought down by the rapid-flowing 

 Hutt River. This plain is rapidly advancing into the harbour, thus 

 decreasing the area of that feature. 



The time during which the major faulting movements, which have so 

 profoundly influenced the basin of Wellington Harbour and its surround- 

 ings, took place is not certain, but it probably continued from late Tertiary 

 times up to the present. A late Tertiary date for the probable beginning 

 of these diastrophic movements is given because we know that faulted 

 Miocene rocks overlie the southern continuation of the peneplain near 

 Nelson and elsewhere at the northern part of the South Island. 



That seismic movements have taken place recently in and around 

 Wellington is well known to every student of New Zealand geology and to 

 €very Wellingtonian. We owe part of the very limited area of flat land 

 on which a portion of the city is built to one of these tectonic changes — 

 namely, that of the earthquake of 1855. The elevated beaches between 

 • Lyall Bay and Seatoun are a magnificent monumeiat of the same event. 

 They stretch for miles along that wild shore, elevated about 5 ft. above 

 the present high-tide level. In places the surface of the beach bordering 

 the steep marine-denuded cliffs is so flat, and is composed of such fine 

 gravel, that it resembles an artificial embankment. Else where, occur flats, 

 5 or 6 chains wide or even more, surmounted by skerries, which until very 

 recently Avere washed by the waves. Here and there along the seashore 

 fishermen have taken advantage of the recently raised beaches to erect 

 their huts thereon. 



More remote from Wellington, recently elevated beaches are said to exist 

 at Palliser Bay and elsewhere ; while in Porirua Inlet there is an interesting 

 historical proof of the same upward movement. It is said that the man-of- 

 war's boat which captured Te Rauparaha ascended the Pahautanui to his 

 pa, situated at a point near the present bridge on the main road. Now the 

 stream, even in times of flood, is much too shallow to allow an ascent so 

 far in a similar craft. 



The predominant line of faulting in the vicinity of Wellington seems 

 approximately to follow the western shore-line of the harbour, and to this 

 plane of weakness, both past and present, all the other faults by which the 

 graben depression and the blocks of the peneplain have been produced are 

 subsidiary. 



The various faulting movements, both recent and more remote, around 

 the site of WelHngton are probably connected more or less directly with the 

 extensive movements which have influenced the topography at the north- 

 eastern corner of the South Island, where marked seismic activity has been 

 recently exhibited, particularly in the years 1855, 1888, and 1901. 



Proof of the Great Fault along the Western Side of Wellington 



Harbour. 



It will be interesting now to give reasons why we know that there has 

 been in the past extensive movements along the western side of the harbour 

 or along the line of major faulting. Even the most casual observer will 

 note that the slope of the hill is remarkably steep — much steeper than the 



