358 THE STORY OP THE EAETH AND MAN. 



cance. Fifty-seven parallel lines of descent have in 

 Europe run on along with man, from the Post-glacial 

 period, without change or material modification of any 

 kind. Some of them extend without change even 

 farther back. Thus man and his companion-mammals 

 present a series of lines, not converging as if they 

 pointed to some common progenitor, but strictly 

 parallel to each other. In other words, if they are 

 derived forms, their point of derivation from a common 

 type is pushed back infinitely in geological time. The 

 absolute duration of the human species does not affect 

 this argument. If man has existed only six or seven 

 thousand years, still at the beginning of his existence 

 he was as distinct from lower animals as he is now, 

 and shows no signs of gradation into other forms. 

 If he has really endured since the great Glacial period, 

 and is to be regarded as a species of a hundred thou- 

 sand years' continuance, still the fact is the same, and 

 is, if possible, less favourable to derivation. 



bimilar facts meet us in other directions. I have 

 for many years occupied a little of my leisure in 

 collecting the numerous species of molluscs and other 

 marine animals existing in a sub -fossil state in the 

 Post-pliocene clays of Canada, and comparing them 

 with their modern successors. I do not know how 

 long these animals have lived. Some of them certainly 

 go far back into the Tertiary; and recent computations 

 would place even the Glacial age at a distance from us 

 of more than a thousand centuries. Yet after carefully 

 studying about two hundred species, and, of some 



