XVI INTRODUCTION. 



resulting from the rupture of the beds, at the time of the 

 vast subsidence which sunk the former continents, and pro- 

 duced the new concavity of the ocean. 



These theories may be compared with the Wernerian and 

 Huttonian, and that of Ferrara, founded, as he says, on that 

 of Burnet. The rocks having been hitherto considered as 

 the chief province of the geologist, it is hoped these few cur- 

 sory remarks will not be found foreign to the purpose. But 

 Tetralogy, as already observed, has little more connexion with 

 Geology than its sister sciences Lithology or Metallogy; 

 and, like them, can only be regarded as an introduction. In 

 which point of view these observations may not be found 

 unuseful to the student. But it is time to return to the de- 

 scription of the Accidential Domains, an accurate knowledge 

 of which may be regarded as peculiarly indispensable to any 

 system of geology, such theories having so often confounded 

 the pride of human science. The more humble sage will 

 perhaps be contented with the knowledge of the substances 

 themselves, and prefer what Gibbon calls a LEARNED IGNO* 

 EANCE to any geological theory. 



