up
upon the sea-beach, have been imbedded in the ancient sands, or muds, or
limestones, just as they are being imbedded now in sandy, or clayey, or
calcareous subaqueous deposits. They furnish us with a record, the general
nature of which cannot be misinterpreted, of the kinds of things that have
lived upon the surface of the earth during the time that is registered by
this great thickness of stratified rocks.

But even a superficial study of these fossils shows us that the animals
and plants which live at the present time have had only a temporary
duration; for the remains of such modern forms of life are met with, for
the most part, only in the uppermost, or latest, tertiaries, and their
number rapidly diminishes in the lower deposits of that epoch. In the
older tertiaries, the places of existing animals and plants are taken by
other forms, as numerous and diversified as those which live now in the
same localities, but more or less different from them; in the mesozoic
rocks, these are replaced by others yet more divergent from modern types;
and in the palaeozoic formations, the contrast is still more marked. Thus
the circumstantial evidence absolutely negatives the conception of the
eternity of the present condition of things. We can say with certainty
that the present condition of things has existed for a comparatively short
period; and that, so far as animal and vegetable nature are concerned, it
has been preceded by a different condition. We can pursue this evidence
until we reach the lowest of the stratified rocks, in which we lose the
indications of life altogether. The hypothesis of the eternity of the
present state of nature may, therefore, be put out of court.

We now come to what I will term Milton's hypothesis--the hypothesis that
the present condition of things has endured for a comparatively short
time; and, at the commencement of that time, came into existence within
the course of six days. I doubt not that it may have excited some surprise
in your minds that I should have spoken of this as Milton's hypothesis,
rather than that I should have chosen the terms which are more customary,
such as "the doctrine of creation," or "the Biblical doctrine," or "the
doctrine of Moses," all of which denominations, as applied to the
hypothesis to which I have just referred, are certainly much more familiar
to you than the title of the Miltonic hypothesis. But I have had what I
cannot but think are very weighty reasons