Smith. — O71 Changes in Level of Coast Line in North Island. 408 



the sea level, whilst Morrinsville is only 86 feet. Consequently a depression 

 of 100 feet would again bring the sea up to those places, or within 20 miles 

 of Hamilton, thus extending the gulf by an area of 250 square miles. 

 Traces of the old coast line may be detected here and there far inland, but 

 at Miranda it is more than usually distinct. Here we have a low flat, 

 generally swampy, extending back from the coast line, for a mile to the foot 

 of the hills, which fall steeply to its level, where they form contours exactly 

 like the sinuosities of an ocean beach, whilst at one spot, close to the foot 

 of the hiUs, is found an isolated rock jutting out fi.'om the swamp, pinnacled 

 with wave-beaten sides, through which is a cave or passage so clearly the 

 result of water action as to cause surprise at the absence of the waves which 

 made it. Near, too, lying along the foot of the hills, are to be seen large 

 masses of clay slate rocks, just as one sees along a modern beach. The 

 level of the flat here is about 15 feet above high-water mark, and therefore 

 corresponds with the raised beach mentioned by Captain Hutton as existing 

 on the opposite side of the gulf at Shortland. He says, after referring to a 

 submergence which is proved by finding at a depth of 30 feet kauri gum, 

 pieces of wood, and rotten raupo, and nearer Shortland an old Maori 

 paddle. 



" It would thus appear that when the alluvium full of boulders found on 

 the top of the hills was forming, the land was 1,000 feet lower than at pre- 

 sent, that it then gradually rose until it was at least 100 feet higher than 

 now ; and at that time the Thames ran further north than Shortland. The 

 land then sunk to about 10 or 12 feet lower than now, and subsequently 

 has again risen to its present level." 



I have been informed that in the great swamps lying between the Thames 

 and Piako are to be found shell banks and sand banks, now several miles 

 from the sea, which formerly marked the high water line at the level the 

 land then stood at. 



Following the coast northwards from Miranda, the same line of old 

 beaches can be occasionally detected, and in some cases even the old shingle, 

 as rolled by the tide, is visible, but now separated from the sea by long 

 stretches of low- level land and swamps. At Umupuhia, near the mouth of 

 the Wairoa, at about 15 feet above present high water-mark, is a level plain 

 extending through from Waiheke channel to the Wairoa Eiver, which, before 

 the elevation, separated the western head of that river fi'om the mainland, 

 forming an island. Approaching Auckland the line of old sea-level is seen 

 here and there, as at Brown's Island, in Hobson's Bay, the north shore at 

 the Victoria wharf, and at places up the harbour. It is probable that when 

 the sea formed these old beaches there was another entrance to the harbour 

 — namely, by the shallow arm running from Shoal Bay, behind the flag- 



