Charles Lyell, Historian of Time's Cycle - Time's Arrow, Time's Cycle: Myth and Metaphor in the Discovery of Geological Time - page 141

tive proportions on a global scale. The northern hemisphere is now in "the
winter of the 'great year,' or geological cycle"; but we may expect the future
to bring "conditions requisite for producing the maximum of heat, or the
summer of the same year" (I, 116).
Life, to say it once more, follows climates. If the passage from summer to
winter of the great year has brought progress to vertebrate life in the northern
hemisphere, the return of subsequent summer must engender a most curious
result. We come then to that most stunning passage of the entire Principles —
the line that marks Lyell as a theorist dedicated to consistency, not always to
empirical restraint (as legend holds); the conjecture so outré (even to Lyell's
contemporaries) that De la Beche captured it in caricature, while Frank
Buckland, unable to grasp such a curious context, interpreted it as a jest about
his father rather than a mordant dig at Lyell; the subject of the frontispiece
and first section of this chapter. And so, once more with feeling: "Then might
those genera of animals return, of which the memorials are preserved in the
ancient rocks of our continents. The huge iguanodon might reappear in the
woods, and the ichthyosaur in the sea, while the pterodactyle might flit again
through umbrageous groves of tree-ferns" (I, 123).
But as zealously as Lyell probed behind appearance to impose uniformity of
state upon the apparent record of vertebrate progress, he could not (or dared
not) extend this argument to our own species. Humans are special; humans
are different. The intellectual world is littered with systems that pushed
consistency to the ends of the earth and the bounds of rationality, but then
stepped aside and made an exception for human uniqueness. Lyell followed
this tradition and placed a picket fence around Homo sapiens.
Lyell does note, quite fairly, that we often make too much of ourselves and
that our physical bodies are poor and flawed indeed, displaying no mark of
progress in our late appearance: "If the organization of man were such as
would confer a decided preeminence upon him, even if he were deprived of
his reasoning powers ... he might then be supposed to be a link in a
progressive chain" (I, 155).