, as well as the whole series, exhibit a correspondence.

Succession implies time; the lower members of an undisturbed series of
sedimentary rocks are certainly older than the upper; and when the notion
of age was once introduced as the equivalent of succession, it was no
wonder that correspondence in succession came to be looked upon as a
correspondence in age, or "contemporaneity." And, indeed, so long as
relative age only is spoken of, correspondence in succession _is_
correspondence in age; it is _relative_ contemporaneity.

But it would have been very much better for geology if so loose and
ambiguous a word as "contemporaneous" had been excluded from her
terminology, and if, in its stead, some term expressing similarity of
serial relation, and excluding the notion of time altogether, had been
employed to denote correspondence in position in two or more series of
strata.

In anatomy, where such correspondence of position has constantly to be
spoken of, it is denoted by the word "homology" and its derivatives; and
for Geology (which after all is only the anatomy and physiology of the
earth) it might be well to invent some single word, such as "homotaxis"
(similarity of order), in order to express an essentially similar idea.
This, however, has not been done, and most probably the inquiry will at
once be made--To what end burden science with a new and strange term in
place of one old, familiar, and part of our common language?

The reply to this question will become obvious as the inquiry into the
results of palaeontology is pushed further.

Those whose business it is to acquaint themselves specially with the
works of palaeontologists, in fact, will be fully aware that very few, if
any, would rest satisfied with such a statement of the conclusions of
their branch of biology as that which has just been given.

Our standard repertories of palaeontology profess to teach us far higher
things--to disclose the entire succession of living forms upon the
surface of the globe; to tell us of a wholly different distribution of
climatic conditions in ancient times; to reveal the character of the
first of all living existences; and to trace out the law of progress from
them to us.

It may not be unprofitable to bestow on these professions a somewhat more
critical examination than they have hitherto received, in order to
ascertain how far they rest on an irrefragable basis; or whether, after
all, it might not be well for pal