CHAP. II. 



On the particular Objects and Ends of Geological 



Investigation. 







A VERY superficial examination of the objects which 

 surround us, is sufficient to show that the substances 

 which constitute the accessible portions of the globe, 

 are numerous and various, and that their positions and 

 mutual relations are irregular and intricate. Granite 

 and marble, slate and sandstone, furnish the materials 

 of architecture, the metals and coal are the foundation 

 of the arts. The same rocks that constitute the ridge 

 of Jura occupy the plains of England, and the basalts 

 that repose on the granites of the Andes are found 

 beneath the limestones of Sky. A thousand pheno- 

 mena record the revolutions which these substances 

 have undergone. The fragments of former rocks are 

 reconsolidated to form new mountains, the remains of 

 animals that have existed beneath the ocean are im- 

 bedded in the loftiest Alps, and the vegetables that 

 once flourished in the light of day are buried beneath 

 the solid strata. 



A very general view of* the objects which comprise 

 the immediate pursuit of the geologist, will here be 

 sufficient. The most obvious of these is the nature of 

 the rocks which constitute the accessible portions of 

 the globe ; and, in these, it is necessary to distinguish 

 the mineral composition, the peculiarities of structure, 

 the varieties which they may present, and the families 

 or species into which they have been already divided, 



