49 Transactions.— Miscellaneous. 
solution, and scrutinized closely the merits of my explanation, it failed to 
stand the test of that examination. The question to be solved was the 
following: You are, without doubt, all aware that the rivers on the Canterbury 
Plains have the tendency to undermine their banks, consisting of loose 
fluviatile deposits, on their left or northern side, and that they have done this 
already so effectually that, in their lower course and for a considerable dis- 
tance, their right or southern banks are always low, and possess scarcely any 
terraced appearance, whilst they continue, generally to the very sea-shore, to 
be fringed on their left banks by a high terrace or cliff. To give only one 
instance, I wish to point to the Rangitata, where the railway erosses it, and 
where we have to descend considerably before we can reach the river-bed, 
which, on the southern side, is only bounded by low ground. It must 
strike even the casual observer that, whilst the left bank forms, as far as 
the eye can reach, a high and conspicuous cliff, the right bank is so very 
low and ill-defined that the river continually changes its course. 
With many geologists who had observed similar phenomena in other 
countries, I had tried to explain this peculiar tendency of our rivers by 
assuming a small oscillation of this portion of the South Island, the North 
gradually sinking and the South rising, by which the waters of all the 
rivers flowing through it would be thrown towards their northern banks; 
but when I searched for evidence all round Banks Peninsula, or at Timaru 
and Double Corner, for this supposed partial sinking and rising of the 
ground, the evidenee before me did not warrant such an assumption. 
Some time ago I found in Professor von Hochstetter's excellent geological 
hand-book, ** Die Erde," reference to a theory first set forth by Carl Ernst 
von Baer, the eminent physiologist and anatomist, but who was equally 
distinguished as a physical geographer, by which that peculiar feature of 
our rivers is fully explained. Although von Baer could only base his 
theory on the rivers of the northern hemisphere, and then principally 
upon those of Russia and Western Biberia, it will be seen that it is fully 
borne out by our own rivers. These latter, moreover, prove the universality 
of the phenomenon, with the exception, as von Baer prognosticated, that 
the opposite banks of the rivers in the southern, when compared with 
the northern hemisphere, would be affected. 
It is long ago that the observation was made on several rivers in 
Europe and Northern Asia, which are enclosed in banks of loose material, 
that they continually and steadily try to advance towards the right, and 
that consequently they wash away and undermine their right banks. Many 
explanations were given, principally (as I had tried with our own rivers) by 
assuming local changes in the level of the earth’s crust; but the generality 
of the phenomenon made such an explanation impossible, 
