I ON A PIECE OF CHALK 35 



identically the same as those which lived in the 

 times called " older tertiary/' which succeeded the 

 cretaceous epoch ; and the crocodiles of the older 

 tertiaries are not identical with those of the 

 newer tertiaries, nor are these identical with 

 existing forms. I leave open the question whether 

 particular species may have lived on from epoch 

 to epoch. But each epoch has had its peculiar 

 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 ? 



"VOnly 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. TjTcan 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 pro- 

 ceedings 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 



