Geoscience Reference
In-Depth Information
Figure 10.3 Charles Darwin
(1809-1882). Photograph by
Elliott and Fry, 55 Baker Street.
Author's collection.
features. Andrew Crombie Ramsay (1814-1891), later Director of the
Geological Survey of Great Britain, who was responsible for the figure
of 72,000 feet for the British sedimentary pile, had told Darwin that
several formations, or distinctive horizons, were on average 1,100 feet
thick. Now he produced his startling conclusion: that as denudation
rates were 1 inch per hundred years in his estimate, it was obvious that
it had taken 306,662,400 years to produce the Wealden landscape, a
process that had been ongoing since the Mesozoic. Three hundred
million years! This was a fantastic figure, and yet Darwin said that
the stripping off of this material was 'a mere trifle, in comparison with
that which has removed masses of our Palæozoic strata', a time-span
he did not attempt to quantify. Perhaps this was just as well, because it
would have been far greater than the 300 million years for the Weald.
Phillips, and many other geologists, could not fathom this conclusion
at all. He could not accept the main Darwinian thrust, that of natural
