Wells. — On the Drift Beds of Wakapuaka. 849 



way into the inner lagoon from the upper end of the bank. Should this 

 happen, it would of course speedily change the character of the district, and 

 might have important effects on the lower part of the township itself. I do 

 not state this as an alarmist, as artificial means might be employed to 

 support the weak points in the bank as they occur ; but there is no doubt 

 that inroad at the present time is being made by the heavy swell which 

 strikes the bank in its upper portion, and symptoms of degrading influences 

 are already showing themselves. 



Another geological feature in this district, and connected with drift 

 material, is the basin or mud flat between the main land and boulder bank, 

 which is being silted up, and will at no very distant period be dry land and 

 covered with natural pasture — " provided no intervening circumstances 

 occur" — without any artificial aid more than the forces employed at the 

 present time. Since I first lived in the district, nearly forty years ago, I 

 perceive a considerable change in this direction ; from 1 foot to 3 feet in 

 some places of mineral deposit has been laid down in the upper part of the 

 lagoon during that period. I also perceive a very considerable change in 

 the character of the material now deposited from what it was at a former 

 period, which was then more of an argillaceous decomposed vegetable ooze, 

 in which you sunk to the boot-tops in crossing over to the Boulder Bank at 

 ebb tide. Now we have over that a firm layer of clay deposit on which you 

 may walk over on the upper part of the flat in a pair of slippers without 

 soiling them. This is accounted for by the settlers disturbing the surround- 

 ing country in their farming operations, which the rains and intersecting 

 rivulets bring down to the sea-level, the silt being more of a consistent clay 

 material than the deposit of a former period. This is a very good example 

 of how sedimentary strata are determined by surrounding circumstances. In 

 sinking a vertical shaft in the earth's crust, we find one layer overlying 

 another, having different mineral characteristics. These lie over one 

 another like leaves in a book, and it is the business of the geologist to turn 

 over these leaves, where he finds a true and accurate history of what the 

 surrounding country presented from time to time — the animals and plants 

 then alive upon its surface, and external events faithfully photographed for 

 asons of years in our earth's history. 



I may before closing this paper mention a few of the historical drift 

 beds now in course of formation, although I have no doubt you are all 

 acquainted with them in the course of your reading. The lower basin of 

 the Mississippi shows a drift bed at the present time to the extent of 700 

 miles in length, formed from the sediment brought down this river and its 

 tributaries, from the lands and degraded mountain ranges in the upper dis- 

 tricts of the country. This bed is being daily added to, and no doubt at 



