The earlier students of geology arranged the outline of the order of the
fossils by a rather general comparison with the series of modern life
forms, which happened to agree fairly well with the order in which they
had found the fossils occurring in England and France. But only a block
out of the middle of the complete card index could be made up from the
rocks of England and France; the rest has had to be made up from the
rocks found elsewhere. Louis Agassiz did herculean work in rearranging
and trimming this fossil card index so as to make it conform better, not
only to the companion card index of the modern forms of life, but also
to that of the embryonic series. From time to time even now
readjustments are made in the details of all three indexes, the fossil,
the modern, and the embryonic, the method of rearrangement being
charmingly simple: _just taking a card out of one place and putting it
into another place_ where we may think it more properly belongs. And
then if we can convince our fellow scientists over the world that our
rearrangement is justified, our adjustment will stand,--until some one
else arises to do a better job. When a new set of rocks is found in any
part of the world it is simplicity itself for any one acquainted with
the fossil index system to assign these new beds to their proper place,
though of course the one doing this must be prepared to defend his
assignment with pertinent and sufficient taxonomic reasons.

In view of these facts, we need not be concerned as to the fate of the
geological classification of the fossils. It is a purely artificial
system, just as is the modern classification; but both are useful, and
so far as they represent true relationships they will both stand
unaffected by any change we may make in our opinions as to how the
fossils were buried. But in view of this purely artificial character of
the geological series, what a strange sight is presented by the usual
methods employed to "prove" the exact order in which evolution has taken