XVIII. 



THERE are not a few persons still to be met with, who 

 believe that man and the lower animals appeared 

 simultaneously upon the face of the earth. Geology 

 most forcibly proves the error of such an idea, for 

 although the fossilized remains of every other class 

 of organized beings have been discovered, human 

 bones have nowhere been found. This fact, though 

 deeply interesting, is perhaps not more so than many 

 others which this wonderful science has unfolded. 

 What can be more startling to the student for 

 instance, than the information that for a long period, 

 it may be thousands of years, no species of fish 

 whatever inhabited the primeval seas ? True it is 

 that certain creatures occupied the shallows and 

 depths of ocean, but these were of the lowest type. 

 The most conspicuous were the coral polypes, which 

 even then as now were ever industriously build- 

 ing up lasting monuments of their existence, as the 

 Trilobites, a group of Crustacea, and the Crinoids, 

 or Lily-stars. 



