THE HUMAN SPECIES* 23 



and fierce species, organized to submit to some law of 

 decreasing vitality, yet more than to a cataclystic de- 

 struction. 



Here, then, we have the heads of those preliminary 

 considerations, which demand some notice of the great 

 disturbances that have affected the earth's surface, 

 since the tertiary period came into operation, and our 

 present zoology started into being. Next will be found 

 requisite, a few details on the bone deposits before 

 mentioned, by whatever agency they may have been 

 formed ; for, as by the former the primordial nations 

 may have been forcibly scattered, so, by the latter, 

 Iheir actual existence in regions now separated by 

 oceans, appear to be indicated. 



