Wzurs.—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 8 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 
eons 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 
