252 THEORY OF THE EARTH. 



Such is the precise enumeration of the succes- 

 sive masses with which nature has enveloped the 

 globe. The positive geological information pre- 

 sented by it, has been obtained, by combining the 

 knowledge furnished by mineralogy with that 

 presented by the sciences connected with organic 

 existence. This order, so new and so interesting 

 in facts, has only been acquired by geology, since 

 it preferred positive knowledge, furnished by ob- 

 servation, to fanciful systems, contradictory conjec- 

 tures regarding the first origin of the globe, and all 

 those phenomena, which, having no resemblance 

 to what actually takes place in nature, could nei- 

 ther find in it, for their explanation, materials 

 nor touchstone. A few years ago, the greater 

 number of geologists might have been compared 

 to historians, who, in writing the history of France, 

 should have interested themselves only about the 

 events which had taken place among the Gauls be- 

 fore the time of Julius Cesar. In composing their 

 romances, however, these historians would have 

 taken advantage of their knowledge of posterior 

 facts ; and the geologists of whom I speak, abso- 

 lutely neglected the posterior facts, which could 

 alone have reflected some light upon the darkness 

 of preceding times. 



