Smith. — On Changes in Level of Coast Line in ±\^orth Island. 407 



know Mercury Bay will recognise in the extensive flats to the west of the 

 mouth of the river of that name, the work of elevation aided also by the 

 formation of land by the sea itself, an operation which is the very reverse of 

 its usual action. Here, along the Buffalo beach, we find a series of slightly 

 raised parallel sandhills, divided from one another by lines of swamps, fol- 

 lowing closely the contour of the present coast. These are caused by the 

 wind drifting the sand off the beach at low-water into low hillocks above 

 high-water mark, which, after a time, become covered with vegetation, when 

 others arc formed in front of them, the intervening hollows being gradually 

 filled with swamps. Another raised beach is to be found to the east of 

 Shakespeare's cliff ; indeed, in several places along the coast towards Kati- 

 kati. 



Tauranga Harbour presents some interesting changes due to elevation. 

 Prior to the upheaving of the present coast-line the sea probably washed the 

 southern shores of the harbour all the way from Katikati to Te Papa, leaving 

 the higher parts of Matakana Island as low islands off the shore. On the 

 elevation taking place, the sands have gradually accumulated sufficient to 

 form Matakana Island some twenty miles long, to which is due the present 

 harbour. At that time Mangonui mount was an island, as was also Mata- 

 pihi, which latter formed part of the sea-bottom prior to the older elevation 

 referred to. From Tauranga to Maketu the old coast-line can be readily 

 traced, where the steep hills sloping down from Otanewainuku end abruptly 

 on the level and swampy foreshore. At Maketu the coast-line receded suffi- 

 ciently far back to form a deep bay, in which that place stood as a flat 

 island, which it also was before the ancient elevation took place, and at 

 which time the flat surface of Motiti Island formed part of the floor of the 

 ocean. 



The evidence is everywhere the same as we follow along to and beyond 

 Opotiki Cliffs, which have been worn by the sea, are now separated from it 

 by low flats generally sandy and swampy, whilst at Matata there was a deep 

 bay running inland, now filled with swamps and sands, due partly to river 

 action, aided by elevation. The isolated slate-rock at Whakatane, close to 

 the township, under the shade of which Te Kooti's men slept off the effects 

 of their potations after the sack of that place, clearly demonstrates this 

 elevation. No one, looking at the rock, can doubt the fact of the sea having 

 separated it from the main, when the waves rose some 15 feet higher. The 

 fertile flats of Opotiki are due to the alluvium brought down by the two 

 rivers Otara and Waioeka, deposited in an estuary of the former sea. The 

 so-called table-land of Opotiki is part of a much more ancient sea-beach or 

 bottom, which can be traced from the East Cape to Katikati. It is every- 

 where on a much larger scale than the one hitherto described, and forms 



