s altered climate, or
the migration into their territory of more masterful species. Past and
present causes are one--natural law is changeless and eternal.

Such was the essence of the Huttonian doctrine, which Lyell adopted and
extended, and with which his name will always be associated. Largely
through his efforts, though of course not without the aid of many other
workers after a time, this idea--the doctrine of uniformitarianism, it
came to be called--became the accepted dogma of the geologic world not
long after the middle of the nineteenth century. The catastrophists,
after clinging madly to their phantom for a generation, at last
capitulated without terms: the old heresy became the new orthodoxy, and
the way was paved for a fresh controversy.

THE ORIGIN OF SPECIES

The fresh controversy followed quite as a matter of course. For the idea
of catastrophism had not concerned the destruction of species merely,
but their introduction as well. If whole faunas had been extirpated
suddenly, new faunas had presumably been introduced with equal
suddenness by special creation; but if species die out gradually,
the introduction of new species may be presumed to be correspondingly
gradual. Then may not the new species of a later geological epoch be
the modified lineal descendants of the extinct population of an earlier
epoch?

The idea that such might be the case was not new. It had been suggested
when fossils first began to attract conspicuous attention; and such
sagacious thinkers as Buffon and Kant and Goethe and Erasmus Darwin
had been disposed to accept it in the closing days of the eighteenth
century. Then, in 1809, it had been contended for by one of the early
workers in systematic paleontology--Jean Baptiste Lamarck, who
had studied the fossil shells about Paris while Cuvier studied the
vertebrates, and who had been led by these studies to conclude that
there had been not merely a rotation but a progression of life on the
globe. He found the fossil shells--the fossils of invertebrates, as he
himself had christened them--in deeper strata than Cuvier's vertebrates;
and he believed that there had been long ages when no higher forms than
these were in existence, and that in successive ages fishes, and then
reptiles, had been the highest of animate creatures, before mammals,
including man, appeared. Looking beyond the pale of his bare facts,
as genius sometimes will, he had insisted that these progressive
population