Smith. — On Changes in Level of Coast Line in North Island. 409 



beach, are relics of old Maori encampments. This raised beach continues 

 as far as Makarori rocks, which are comparatively horizontal, and belong 

 to the sandstone formation of the Leda marl series." 



The extensive flats of Poverty Bay are no doubt due partly to elevation, 

 the richness of the soil being accounted for by the deposition of alluvium 

 in a former estuary. 



Coming now to the southern boundary of this provincial district, we find 

 that the thirty-ninth parallel of latitude strikes the sea at Te Mahanga, 

 about four miles north of Te Mahia peninsula, on a low swampy and sandy 

 flat, evidently an old sea beach, as the coast line may be traced running 

 round some three miles inland, where the steep hills suddenly end on the 

 flat. This plain which is of considerable extent, is generally not more than 

 fifteen or twenty feet above high water mark, and were a depression to that 

 amount to take place the Mahia would again become an island. 



From what has been said, it is tolerably clear that the balance of 

 evidence is in favour of elevation going on during the later geological ages, 

 and that it has been pretty general all over this northern part of the Island ; 

 that there are two tolerably distinct Hues of possibly sudden elevation, 

 whilst others no doubt exist, and that the intermediate period between the 

 two has probably been one of slow gradual rising, with perhaps some local 

 oscillations of an opposite character. The more ancient level is most dis- 

 tinct in the Bay of Plenty, and was most likely coeval with the time when 

 the sea occupied the valley of the Thames, and when the Waikato River 

 emptied itself into that estuary instead of taking its present unnatural 

 course right through two ranges of mountains, and then to the west coast 

 as now. A somewhat similar sea-bottom (perhaps not so high above 

 present high water-mark) can, I think, be traced even here near Auckland. 

 At this period there was a channel through to Kaipara. It is obvious that 

 owing to the length of time that has elapsed since this ancient coast line 

 was in existence that the evidence of it must be much more obscure. 

 During the ages that have passed, the power of running water has had 

 time to exert its influence in cutting out deep gullies, or in planing the 

 former level sea-bottom into slopes of different degrees, leaving only here 

 and there some slight indications still to be found, but yet sufficient to 

 warrant the probability of the supposition, more especially as the shape 

 and contour of the ground in many places is explicable only on the theory 

 of a plane of marine denudation. 



As to whether the land is still rising, I would observe that the action 

 of the elevatory forces is usually so exceedingly slow that the time we have 

 been in occupation of the country has hardly been long enough to allow us 

 to form ail opinion. Lyell, in his classical work " The Principles of 

 Geology," quotes the case of Norway as a country rapidly rising, and this is 



62 



