s, left impressed
on the sands over which they stalked of old. This early Oolitic volume
corresponds in its contents to the section devoted by Cuvier, in his
great work, to his second class, the birds. And in the Stonisfield
slate,--a deposit interposed between the "Inferior" and "Great
Oolites," we detect the earliest indications of his first or
mammaliferous class, apparently represented, however, by but one
order,--the Marsupiata, or pouched animals, to whose special place in
the scale I shall afterwards have occasion to refer. Not until we reach
the times of the Tertiary division do the mammals in their higher orders
appear. The great Tertiary volume corresponds to those volumes of Cuvier
which treat of the placental animals that suckle their young. And
finally,--last born of creation,--man appears upon the scene, in his
several races and varieties; the sublime arch of animal being at length
receives its keystone; and the finished work stands up complete, from
foundation to pinnacle, at once an admirably adjusted occupant of space,
and a wonderful monument of Divine arrangement and classification, as it
exists in time. Save at two special points, to which I shall afterwards
advert, the particular arrangement unfolded by geologic history is
exactly that which the greatest and most philosophic of the naturalists
had, just previous to its discovery, originated and adopted as most
conformable to nature: the arrangements of geologic history as exhibited
in time, if, commencing at the earliest ages, we pursue it downwards, is
exactly that of the "Animal Kingdom" of Cuvier read backwards.

Let us then, in grappling with the vast multiplicity of our subject,
attempt reducing and simplifying it by means of the classifying
principle; not simply, however,--again to recur to the remark of the
metaphysician,--as an internal principle given us by nature, but as an
external principle _exemplified_ by nature. Let us take the organisms of
the old geologic periods in the order in which they occur in time;
secure, as has been shown, that if our chronology be correct, our
classification will, as a consequence, be good. It will be for the
natural theologians of the coming age to show the bearing of this
wonderful fact on the progress of man towards the just and the solid,
and on the being and character of man's Creator,--to establish, on the
one hand, against the undue depreciators of intellect and its results,
that in certain departmen