kes it so difficult to
conceive of all the changes in the earth's surface-features and its
inhabitants being due to similar operations to those still going on
around us.

Lyell's views have constantly been misrepresented by the belief being
ascribed to him that 'the forces operating on the globe have never acted
with greater intensity than at the present day.' But his real position
in this matter was a frankly 'agnostic' one. 'Bring me evidence,' he
would have said, 'that changes have taken place on the globe, which
cannot be accounted for by agencies still at work _when operating
through sufficiently long periods of time_, and I will abandon my
position.' But such evidence was not forthcoming in his day, and I do
not think has ever been discovered since. Professor Sollas has very
justly said, 'Geology has no need to return to the catastrophism of its
youth; in becoming evolutional it does not cease to remain essentially
uniformitarian[149].'

Alfred Russel Wallace, who has always been as stout a defender of the
views of Lyell as he has of those of Darwin, has given me his permission
to quote from a letter he wrote me in 1888. After referring to what he
regards as the weak and mistaken attacks on Lyell's teachings, 'which
have of late years been so general among geologists,' he says:--

'I have always been surprised when men have advanced the view
that volcanic action _must_ have been greater when the earth was
hotter, and entirely ignore the numerous indications that both
subterranean and meteorological forces, even in Palaeozoic
times, were of the same order of magnitude as they are now--and
this I have always believed is what Lyell's teaching implies.'

I believe that Mr Wallace's expression, adopted from the mathematicians,
'the same order of magnitude,' would have met with Lyell's complete
acquiescence. He was not so unwise as to suppose that, in the limited
periods of human history, we must necessarily have had experience--even
at Krakatoa or 'Skaptar Jokull'--of nature's greatest possible
convulsions, but he fought tenaciously against any admission of
'cataclysms' that would belong to a totally different category to those
of the present day.

Apart from theological objections, the most formidable obstacle to the
reception of evolutionary ideas had always been the prejudice against
the admission of vast duration of past geological time. It was
unfortunate that, even when rational hist