trata, containing organic remains, in different
localities. The series resemble one another, not only in virtue of
a general resemblance of the organic remains in the two, but also
in virtue of a resemblance in the order and character of the serial
succession in each. There is a resemblance of arrangement; so that the
separate terms of each series, as well as the whole series, exhibit a
correspondence.

Succession implies time; the lower members of a 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 paleontology is pushed further.

Those whose business it is to acquaint themselves specially with the
works of paleontologists, 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 paleontology 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
firs