V.—_GEOLOGY. 
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Art. LXVIII.—On the Formation of Lake Wakatipu. By Wrtu1am Stuart. 
[Read before the Southland Institute, 19th August, 1881.] 
Tue Wakatipu Lake is deepest about half way between its two ends, near 
the Queenstown bend. The depth is very great, probably the bottom is 
below sea-level, at any rate it is below the level of the Waimea and Dipton 
Plains. During occasional visits to this lake, I have been ‘‘ exercised” to 
use an old theological expression) to account for this. I know that some 
have tried to explain it by the theory that the lake bottom had been scooped 
out to great depth by glacier action. But this was difficult to imagine, 
Having had occasion during the last twelve months to visit the locality, I 
carefully examined the country, and came to the conclusion that, whatever 
may be the case with the neighbouring lakes, the Wakatipu has been 
formed in much the same way as several of the lakes on the southern side 
of the Alps in Europe—namely, by the subsidence of the great mountain 
chain on the side of which it lies. 
That the Wakatipu country has been subject to upheaval and subsidence 
is clear enough, but the mode of the last subsidence isnot soclear. At first 
sight it would appear, to judge from the plains on the east side of the 
Southern Alps, and from the fiords on the west (these latter being mountain 
valleys into which the sea has come), that the island had risen gently on one 
side of the central chain (as an axis), and had subsided heavily on the other, 
but a closer examination, I think, will show that this is not what happened. 
It looks rather as if the island—at any rate this end of it—had gradually 
sunk as from a hinge from the present east coast line, or more probably 
from a line far to seaward beyond it. That this end of the island did subside 
in the manner I describe, is proved, I think, by the existence of the fiords 
and the comparative shallowness of the sea on the west coast, and by the fact 
that the seaward moss (which is now gradually rising) shows the remains 
close to the surface of a submerged forest destroyed in a comparatively recent — 
time. A subsidence in this way would be greatest furthest from the hinge, 
and least near it—the sea would consequently come over a fringe of land, 
and be shallow on the east, and would cover much land devel cp the west. 
Now the alpine range, before the subsidence I am speaking of, un- 
tedly stood at a much higher elevation than at 
__ More likely 10,000 feet, as the hee igo om the west side of Fiord © ae 
