re in fact
intermediate or connecting links." Darwin himself had shown some years
before that the fossil animals of any continent are closely related to
the existing animals of that continent--edentates predominating, for
example, in South America, and marsupials in Australia. Many observers
had noted that recent strata everywhere show a fossil fauna more nearly
like the existing one than do more ancient strata; and that fossils from
any two consecutive strata are far more closely related to each other
than are the fossils of two remote formations, the fauna of each
geological formation being, indeed, in a wide view, intermediate between
preceding and succeeding faunas.

So suggestive were all these observations that Lyell, the admitted
leader of the geological world, after reading Darwin's citations, felt
able to drop his own crass explanation of the introduction of species
and adopt the transmutation hypothesis, thus rounding out the doctrine
of uniformitarianism to the full proportions in which Lamarck had
conceived it half a century before. Not all paleontologists could follow
him at once, of course; the proof was not yet sufficiently demonstrative
for that; but all were shaken in the seeming security of their former
position, which is always a necessary stage in the progress of thought.
And popular interest in the matter was raised to white heat in a
twinkling.

So, for the third time in this first century of its existence,
paleontology was called upon to play a leading role in a controversy
whose interest extended far beyond the bounds of staid truth-seeking
science. And the controversy waged over the age of the earth had not
been more bitter, that over catastrophism not more acrimonious, than
that which now raged over the question of the transmutation of species.
The question had implications far beyond the bounds of paleontology, of
course. The main evidence yet presented had been drawn from quite other
fields, but by common consent the record in the rocks might furnish a
crucial test of the truth or falsity of the hypothesis. "He who rejects
this view of the imperfections of the geological record," said Darwin,
"will rightly reject the whole theory."

With something more than mere scientific zeal, therefore,
paleontologists turned anew to the records in the rocks, to inquire what
evidence in proof or refutation might be found in unread pages of the
"great stone book." And, as might have been expected, many m