Hon. Mr. Strangways on the Rapids of Imatra . 343 
the retiring one on the west, which corresponds to it; which 
cannot be better understood than by imagining the whole channel 
an immense fissure or gap, parallel to the laminae of the rock. 
The uniform width of the valley, the general level of the rocky 
table above described, its furrowed surface strewed with pebbles 
and boulders perforated and shaped with greater minuteness and 
indicating more waste of time than appears in those which have 
been subjected only to the diluvian waters, and the case of the 
block which has been drilled perpendicularly with a cylindrical 
hole, shew the probability there is that the river once extended 
from hill to hill, forming a sheet of water equal in breadth to what 
it now presents above and below the gorge, and full of insulated 
rocks scattered throughout its whole bed. 
From the softness and peculiar nature of the rock, (possibly also 
some small pre-existing fissure, along the line ot the present channel, 
having once allowed the stream to hollow itself a bed in that 
direction sufficiently deep to contain all its waters) this table land 
has been gradually left dry, and at last appears at so considerable a 
height above the daily sinking level of the river ; which may in 
process of time produce similar phenomena in the stony parts of 
the wider basins near Sitola, although the direction of the channel 
which the stream must find for itself will of course vary with 
circumstances. 
It is needless to say, that the observation of the gradually falling 
level of the waters of the Voxa, and of the lake Saima, of which it 
is the only outlet, greatly favours every part of this theory. The 
increase of current, from the confinement of the stream to so narrow 
a channel, will account for the great depth to which it has sunk, 
considering also the nature of the rock. 
Vol, V. 
