a better idea of the scale of these phenomena, if (as in the case of
the glaciers) we suppose them to have taken place at corresponding
distances in Europe:--then would the land from the North Sea to the
Mediterranean have been violently shaken, and at the same instant of
time a large tract of the eastern coast of England would have been
permanently elevated, together with some outlying islands,--a train of
volcanos on the coast of Holland would have burst forth in action, and
an eruption taken place at the bottom of the sea, near the northern
extremity of Ireland--and lastly, the ancient vents of Auvergne,
Cantal, and Mont d'Or would each have sent up to the sky a dark column
of smoke, and have long remained in fierce action. Two years and
three-quarters afterwards, France, from its centre to the English
Channel, would have been again desolated by an earthquake and an island
permanently upraised in the Mediterranean.
The space, from under which volcanic matter on the 20th was actually
erupted, is 720 miles in one line, and 400 miles in another line at
right angles to the first: hence, in all probability, a subterranean
lake of lava is here stretched out, of nearly double the area of the
Black Sea. From the intimate and complicated manner in which the
elevatory and eruptive forces were shown to be connected during this
train of phenomena, we may confidently come to the conclusion, that the
forces which slowly and by little starts uplift continents, and those
which at successive periods pour forth volcanic matter from open
orifices, are identical. From many reasons, I believe that the
frequent quakings of the earth on this line of coast are caused by the
rending of the strata, necessarily consequent on the tension of the
land when upraised, and their injection by fluidified rock. This
rending and injection would, if repeated often enough (and we know that
earthquakes repeatedly affect the same areas in the same manner), form
a chain of hills;--and the linear island of S. Mary, which was upraised
thrice the height of the neighbouring country, seems to be undergoing
this process. I believe that the solid axis of a mountain, differs in
its manner of formation from a volcanic hill, only in the molten stone
having been repeatedly injected, instead of having been repeatedly
ejected. Moreover, I believe that it is impossible to explain the
structure of great mountain-chains, such as that of the Cordillera,
were the strata, capping the injected axis of plutonic rock, have been
thrown on their edges along several parallel and neighbouring lines of
elevation, except on this view of the rock of the axis having been
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