2. TF Jamieson and isostasy
3. Wright and isokinetics
Scottish sea levels
Catastrophists v uniformitarians
Along the coastline of Scotland,
many features formed by the action of the sea now stand above the reach of the
waves. Raised terraces, shingle ridges, cliffs, stacks, caves, rock platforms
and areas of sediment containing marine shells, seal skeletons and even whale
skeletons, have been remarked on for many years. Interest in this evidence of
higher sea levels has not been confined to scientists. The reports of clerics in
the Statistical Accounts of the eighteenth and nineteenth centuries, early books
on the landscape of the country and comments in newspapers in the early
nineteenth century bear eloquent testimony to the place of these features in the
public psyche.
Given the widespread evidence that the sea once lay higher than today, it is not
surprising that the thoughts of some would turn to explanation. Sea level
changes were cited in the arguments between Catastrophists, who believed that
these levels were somehow evidence of a great flood, perhaps as described in the
Bible, and Uniformitarians, who, whilst not against religion, looked upon the
Old Testament as largely allegorical and believed instead in a more ordered and
rational progression of change. Such arguments raged in Edinburgh at the end of
the eighteenth century, with James Hutton (writing in 1795) and John Playfair
(1802) the proponents of gradual change.
Both Hutton and Playfair believed that the level of the sea surface had remained
essentially stable through time, but as it became clear that there had been at
least one “Great Ice Age”, Charles Maclaren in 1842 deduced that with expanded
glaciers and ice sheets, sufficient water would have been abstracted from the
hydrological cycle to lower the level of the oceans and seas of the world, a
view increasingly supported in subsequent years. Uniformitarianism had not been
overturned, but an element of dynamic change had been introduced into the sea
level story.
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