Charles Lyell, Historian of Time's Cycle - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 170

lution provoked Lyell's reconsideration—and that his personal linkage of
transmutation with progress 9 forced his reassessment once Darwin had
convinced him to accept evolution. Lyell was, of course, one of Darwin's
principal friends and confidants, a party to the "delicate arrangement" that
printed Wallace's separate discovery of natural selection along with an earlier
unpublished manuscript of Darwin's, thus affirming Darwin's priority.
Charles Darwin was instrumental in provoking Lyell's assent to evolution,
and this reversal also enters the 1866 revision of Principles.
But a remarkable series of documents—seven private journals "on the species
question" compiled by Lyell between 1855 and 1861 and first published by
L. G. Wilson in 1970—forces us to reverse this conventional argument
toward a new interpretation that makes more sense in terms of human
psychology, as usually expressed.
The notebooks record that Darwin first broached his theory to Lyell during a
visit at Down in April 1856. (Lyell knew, of course, that Darwin had been
working on "the species problem," and that he accepted the common heresy
of evolution, but Darwin had not previously revealed his mechanism of
natural selection to Lyell.) The journals also show that Lyell was already
obsessed with doubt about his linchpin of nonprogressionism in life's history.
All accumulating evidence tended to refute his conviction, particularly the
discovery of human artifacts in young sediments. He had already, before
Darwin's revelation, come to the most reluctant conclusion
9. This, in itself, underscores a curious point. No logical necessity can extract an
implication of progress from the fact of evolution. Darwin himself had maintained a
very ambiguous attitude toward the idea of progress, accepting it provisionally as a
feature of parts of the fossil record, but denying that the theory of natural selection
—a statement about adaptation to shifting local environments— required organic
advance. Nonetheless, many evolutionists have always viewed the concepts of
progress and transmutation as necessarily connected, and Lyell, for whatever
reason, certainly adopted this view. Therefore, for him, a decision to embrace
evolution also entailed progress as a fact: "The progression theory, which accounts
for man being improved out of an anthropomorphous species, is natural the moment
we embrace the Lamarckian view" (in Wilson, 1970, 59).