458 Transactions. — Geology. 



we may judge from the growth of some of the larger of the 

 forest-trees, which indicate an age of between two and three 

 thousand years— perhaps more. 



The left bank of the river near its mouth consists of an 

 immense tract of fiat land, containing several thousand acres, 

 and known as the Tokatoka Swamp, the whole of which, 

 no doubt, has been carried down and deposited by the river. 

 The swamp is on the north-eastern side of the Kaipara 

 Harbour, and the prevailing winds are south-westerly. The 

 effect of these has been to cause the water, with its load of 

 mud, to spread out towards the opposite shores. In this way 

 the north-eastern side was gradually filled up and converted 

 into land. The process of deposit has by no means stopped. 

 The southern portion of the swamp gradually becomes lower 

 until it ends in a wide mud-flat covered with mangroves, 

 where a constant detrital deposit is going on, with the result 

 that the bank is being pushed out further and further into the 

 harbour. Owing to the continual deposit the river-channel is 

 now confined to the shore-line along the western side. 



The land of which the swamp consists is extremely fertile, 

 and has given magnificent returns to those who have been 

 fortunate enough to secure it. A good deal of work in drain- 

 ing and surveying has been done by the Government, and 

 already several blocks have been disposed of by ballot. Some 

 difficulty was at first experienced in obtaining water, but this 

 has since been overcome by sinking artesian wells. The 

 result of the boiings put down are not without interest as 

 throwing light on the origin of the deposit and the rate at 

 which it was laid down For the following tables giving 

 an account of the borings at Eaupo I am indebted to Mr. 

 E. F. Baff, who personally superintended and directed the 

 operations. It may be explained that Eaupo is the name 

 given to that portion of the swamp already settled. 



Details of Bokings. 



No. 1, at liaiipo. Ft. 



50 ft. soft clay or mud (blue) ... ... 50' 



45 ft. soft sands and mud ... ... ... ... 95 



7 ft. hard clay light-grey in colour ... ... ... lOl^ 



33ft. sandy clay ... ... ... ... ... 135 



19 ft. quicksand. (Dribble of water, drop at a time, rises 



2 ft. 6 in. above ground : tried pump — no better) ... 15-4 

 22 ft. soft sandy mud ... ... ... ... 176 



19 ft. grey clay, changing to brown, with woody particles 190 

 17 ft. sharp sand, ((iood flow of water, which rises 12 ft. 

 above surface of ground, and at 3 ft. above ground gives 

 20 gallons per minute, or 28,800 gallons per twenty- 

 four hours) ... ... ... ... ••• 212 



