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the stages of operation to which we owe the superficial deposits of 
Scotland and the north of Europe generally. It is well known that 
in these last there is one prominent characteristic which is absent 
farther south. I mean the abundant proofs of glacial conditions, or 
an arctic climate. On this subject there is a paper of great interest 
in the last “ Quarterly Journal of the Geological Society,” by Mr 
Jamieson, founded on observations made mainly in the county of 
Aberdeen. The cycle of changes which this geologist thinks can be 
clearly traced, as necessary to account for the superficial deposits of 
our own country, amount to no less than five great epochs, including 
two of submergence and two of elevation, and involving changes of 
level to the extent of more than 2000 feet. Scotland has long ago 
furnished evidence as clear as that founded on the French flint im- 
plements, that at least previous to the last of these elevations man 
had reached her shores, and navigated her rivers and estuaries in 
those rude canoes, hollowed out of trunks of oak by stone hatchets, 
which have been frequently found in elevated beds of silt and gravel 
in the valley of the Clyde. And here we strike upon evidence 
which has some bearing upon the question of time. Closely con- 
nected with the period preceding the last elevation of the land, we 
have proof that an arctic climate prevailed over a large part of the 
northern hemisphere, whose climate is now comparatively temperate. 
But this period seems clearly to have been one of long duration — that 
is to say, of such duration, and lasting under such conditions of com- 
parative rest, as to allow the development of a glacial fauna. Close 
to my own residence on the Clyde, each low ebb exposes numerous 
examples of the Pecten Islandicus , and of those very large Balani, 
which are now confined to arctic seas. These beds of shells, which are 
all of existing species, but of species which have retired from our now 
more genial temperature to a northern habitat, were first described 
by my friend Mr Smith of Jordanhill, and his observations and con- 
clusions have since been abundantly confirmed. We have no know- 
ledge how this period was brought to a close. But there seems to 
be evidence that it had come to an end, and that for a long time 
before the last elevation of the land, and before man had ap- 
peared in Scotland. This seems to be a legitimate deduction from 
the fact that the canoes in the elevated Clyde beds are formed of 
oak of large dimensions and of great age. Forests which afforded 
such timber must have flourished in a climate not much more rigor- 
