crocodiles; though all, since the chalk, have belonged to the modern
type, and differ simply in their proportions, and in such structural
particulars as are discernible only to trained eyes.

How is the existence of this long succession of different species of
crocodiles to be accounted for? Only two suppositions seem to be open to
us--Either each species of crocodile has been specially created, or it
has arisen out of some pre-existing form by the operation of natural
causes. Choose your hypothesis; I have chosen mine. I can find no
warranty for believing in the distinct creation of a score of successive
species of crocodiles in the course of countless ages of time. Science
gives no countenance to such a wild fancy; nor can even the perverse
ingenuity of a commentator pretend to discover this sense, in the simple
words in which the writer of Genesis records the proceedings of the fifth
and six days of the Creation.

On the other hand, I see no good reason for doubting the necessary
alternative, that all these varied species have been evolved from pre-
existing crocodilian forms, by the operation of causes as completely a
part of the common order of nature as those which have effected the
changes of the inorganic world. Few will venture to affirm that the
reasoning which applies to crocodiles loses its force among other
animals, or among plants. If one series of species has come into
existence by the operation of natural causes, it seems folly to deny that
all may have arisen in the same way.

A small beginning has led us to a great ending. If I were to put the bit
of chalk with which we started into the hot but obscure flame of burning
hydrogen, it would presently shine like the sun. It seems to me that this
physical metamorphosis is no false image of what has been the result of