MYSTERIOUS FORMS OF LIFE. 



lie first time the boues and teeth of reptiles. These creatures 

 offer extraordinary interest for us, and we shall take up the 

 study of them in due time. Their empire is known as tue 

 REIGN OF REPTILES. Following this was the REIGN OF MAM- 

 MALS, since their bones are found distributed through the 

 Ccenozoic Great System of strata. Lastly came man. His 

 bones and works are confined to the surface of the earth. 

 They are not found imbedded in solid rocks. This last and 

 highest animal characterizes the REIGN OF MAN. This is a 

 grand progression. These are fundamental conceptions in 

 geological science. They must be made perfectly familiar to 

 the student of Natural history. 



As the reader will desire frequently to refer to this classi- 

 fication of formations and of organic history and geological 

 time, I insert the faqts in a Table : 



TABLE OF GEOLOGICAL HISTORY. 



