Bell. — Physioriraj^h n of Wellingfon llarhoiir. 535 



eastwards along the edge of the harbour and bordering the Hutt Valley 

 to the westward. 



A view from any prominent position in the hills around Port Nicholson 

 discloses an elevated country stretching in all directions, broken by narrow 

 valleys and deep ravines. If this elevated country be viewed from a point 

 on the eastern side of the harbour, one is struck with the general uniformity 

 in height attained by the crests of the various hills on the west side. Since 

 this even skyline is quite independent of the strucj;ure of the country rocks 

 (consisting of highly folded and shattered argillites and grauwackes), it 

 apparently exhibits an elevated plain of erosion, or peneplain. 



When the country to the east of the harbour is viewed from the west, 

 at least three, and possibly more, ridges of hills are evident. In each of 

 these ridges the hills seem to rise to an approximately uniform altitude, 

 though there is a marked difference in the general height of the several 

 ridges. Naturally, the highest ridge visible is that farthest east. Below 

 this inner one the two other conspicuous even-crested ridges stand out in 

 step-like blocks. Apparently the crests of all these ridges represent various 

 levels of the old peneplained surface so well seen to the west of the harbour. 



From a high point on this western land the crests of the hills, though in 



Section, Porirua to Ngahauranga. 



general of uniform height, seem gradually to descend in altitude towards 

 Porirua. 



Geological History. 



It will be interesting, now that we know what the harbour and the 

 surrounding country are like to-day, to recapitulate the changes which 

 have taken place in this part of the world since the very earliest geological 

 periods. 



In late Palfeozoic or early Mesozoic times the sea rolled over much of 

 the area now occupied by the present land-surface of New Zealand, and 

 in the locality of Wellington sands and silts were being deposited on the 

 edge of a land area within that sea. It is impossible to state exactly where 

 that ancient land stood, or how far it extended ; but since we find that the 

 rocks now exposed around Wellington consist of a great series of argillites 

 and grauwackes, which were originally silts and sands or deposits usually 

 laid down close to a land-margin, it may be presumed that the deposition 

 extended over a long period of time along a gradually sinking sea-margin. 



Subsequent to this deposition the sediments thus formed were elevated 

 above sea-level, and folded into anticlines and synclines. So soon as the 

 land had risen above the surface of the sea, and even possibly before it 

 had reached the surface, its wearing-away had commenced. It is not 

 known to what heights the land rose in those ancient times. It may have 

 been low, hilly, or even mountainous country, though from the absence of 

 glacial debris in the formation succeeding the period of elevation it is 

 gathered that, if mountains did exist, they were not elevated to levels of 

 perpetual snow. We do know that after a long period of time, during 

 which erosion was ever active, the land was worn down almost to the level 

 of the sea, producing a peneplain. 



