t imperceptible gradations to the higher and more
complex structures of being. We are struck by the correspondence, by the
_pari passu_ development and formation of the earth's crust and organic
existences, and we are apt hastily to conclude that a relation has
subsisted between them, that contemporary changes have been cause and
effect, and that the improvement of the earth produced the correlative
improvement in animals and plants.

This forms the author's second questionable hypothesis; it is plausible,
but false--repugnant to fact and correct observation. We have no
credible evidence that species have changed, or are changeable by the
utmost efforts of art or favouring conditions; all we can effect is to
improve them within definite limits, but not alter their characteristic
types; and we have certain proof that neither man nor the animal nearly
next to him in organization, has changed either in habits, disposition,
form, or osseus structure during the last 3,000 years. Resemblance is no
proof of identity; and hence, though species run into each other by
almost inappreciable shades of difference, it is no proof that they are
derivative, or other than isolated and self-dependent creations. That
they are such, and shall continue such, seems a fixed canon of Nature,
who, apparently, has prescribed to each its circle of amendment and
range, that like shall beget like--that nought organic shall exist
without ancestral germ--and that the variety of species which
constitutes the beauty and order of nature shall by no chance,
contrivance, or mingling of races, be confounded.

Geological facts are in favour of this conclusion. They attest the
appearance of new species, not their improvement. In each species a
gradation of improvement, approximating from a lower to the next higher
organism, is not perceptible; but each seems to have been made perfect
at first, and most suited to the co-existent state of the earth. The
earliest reptiles were not reptiles of inferior structure; nor the
earliest fishes, birds, or beasts. They were adapted, as we now find
them, to their precise sphere of existence, without progressive
aptitude, preparatory to a higher and translated condition of being.
Geology rather points to the extinction and degeneracy of species than
their improvement; and the fossils of the old red sandstone, and of the
carboniferous formation, attest a loftier and more magnificent creation
of both marine and land products