d by the geologist and
palaeontologist, from sub-Cambrian depths to the deposits thickening
over the sea-bottoms of today. And upon the leaves of that stone book
are, as you know, stamped the characters, plainer and surer than those
formed by the ink of history, which carry the mind back into abysses
of past time, compared with which the periods which satisfied Bishop
Butler cease to have a visual angle.

The lode of discovery once struck, those petrified forms in which life
was at one time active, increased to multitudes and demanded
classification. They were grouped in genera, species, and varieties,
according to the degree of similarity subsisting between them. Thus
confusion was avoided, each object being found in the pigeon-hole
appropriated to it and to its fellows of similar morphological or
physiological character. The general fact soon became evident that
none but the simplest forms of life lie lowest down; that, as we climb
higher among the superimposed strata, more perfect forms appear. The
change, however, from form to form was not continuous, but by
steps--some small, some great. 'A section,' says Mr. Huxley, 'a
hundred feet thick will exhibit at different heights a dozen species
of Ammonite, none of which passes beyond the particular zone of
limestone, or clay, into the zone below it, or into that above it.' In
the presence of such facts it was not possible to avoid the question:
Have these forms, showing, though in broken stages, and with many
irregularities, this unmistakable general advance, being subjected to
no continuous law of growth or variation? Had our education been
purely scientific, or had it been sufficiently detached from
influences which, however ennobling in another domain, have always
proved hindrances and delusions when introduced as factors into the
domain of physics, the scientific mind never could have swerved from
the search for a law of growth, or allowed itself to accept the
anthropomorphism which regarded each successive stratum as a kind of
mechanic's bench for the manufacture of new species out of all
relation to the old.

Biassed, however, by their previous education, the great majority of
naturalists invoked a special creative act to account for the
appearance of each new group of organisms. Doubtless numbers of them
were clearheaded enough to see that this was no explanation at
all--that, in point of fact, it was an attempt, by the introduction of
a greater difficult