ic development, the whole phenomena
appear exactly what might have been anticipated. It is also
remarked, in objection, that the mollusca and articulata appear in
the same group of rocks (the slate system) with polypiaria,
crinoidea, and other specimens of the humblest sub-kingdom; some of
the mollusca, moreover, being cephalopods, which are the highest of
their division in point of organization. Perhaps, in strict fact,
the cephalopoda do not appear till a later time, that of the
Silurian rocks. But even though the cephalopoda could be shewn as
pervading all the lowest fossiliferous strata, what more would the
fact denote than that, in the first seas capable of sustaining any
kind of animal life, the creative energy advanced it, in the space
of one formation, (no one can say how long a time this might be,)
to the highest forms possible in that element, excepting such as
were of vertebrate structure. It may here be inquired if geologists
are entitled to set so high a value as they do upon the point in
the scale of organic life which is marked by the upper forms of the
mollusca. It will afterwards be seen that this is a low point
compared with the whole scale, if we are to take as a criterion
that parity of development which has been observed in the embryo of
one of the higher animals. _The human embryo passes through the
whole space representing the invertebrate animals in the first
month, a mere fraction of its course._ There is indeed a remarkably
rapid change of forms in such an embryo at first: the rapidity,
says Professor Owen, is 'in proportion to the proximity of the ovum
to the commencement of its development;' and, conformable to this
fact, we find the same zoologist stating that, in the lowest
division of the animal kingdom, (the Acrita of his arrangement,)
there is a much quicker advance of forms towards the next above it,
than is to be seen in subsequent departments. There is, indeed, to
the most ordinary observation, a rapidity and force in the
productive powers of the lowest animals, which might well suggest
an explanation of that rush of life which seems to be indicated in
the slate and Silurian rocks. With regard to the so-called early
occurrence of fishes partaking of the saurian character, I would
say that their occurrence a full fo