strata be estimated as about one hundred
and thirty thousand feet, then seventy thousand feet belong to this
epoch. It was during this epoch that the little mass of protoplasm,
which has been so often spoken of, came into existence.

It has been stated above that palaeontology is quite deficient. This is
not only true of the record, but of the lack as yet of sufficient
investigations. The greatest fields of investigation in this department
have never been explored. The whole of the petrifactions accurately
known do not probably amount to a hundredth part of those which, by more
elaborate explorations, are yet to be discovered. The most ancient of
all distinctly preserved petrifactions is the Eozoon Canadense, which
was found in the lowest Laurentian strata in the Ottawa formation.

Probably no discovery in palaeontology ranks higher than the discovery of
the descendants of the horse. The horse, for example, as far as his
limbs and teeth go, differs far more from extant graminivora than man
differs from the ape. Had not fossil ungulates been found, which
demonstrate the common origin of the horse with didactyles and
multidactyles, some would have deemed the horse a special miraculous
creation. But now the links are complete, and the descent of the horse
is found to follow exactly what the doctrine of evolution could have
predicted.

ONTOGENY.

It has been stated that the palaeontological record is quite incomplete,
owing to many facts, some of which have been mentioned; fortunately, the
history of the development of the organic individual, or ontogeny, comes
in to fill up many deficiencies.

Ontogeny is a repetition of the principal forms through which the
respective individuals have passed from the beginning of their tribe,
and its great advantage is that it reveals a field of information which
it was impossible for the rocks to retain; for the petrification of the
ancient ancestors of all the different animal and vegetable species,
which were soft, tender bodies, was not possible.

The annexed plate illustrates the dog, rabbit, and man in their first
stages of development. Illustrations of a fish, an amphibious animal, a
reptile, a bird, or any mammal, could also be given; for all vertebrate
animals of the most different classes, in their early stages of
development, cannot be distinguished, and the nearer the animal
approaches man in the ascending scale, the longer does this similarity
continue to exist--when