GEOLOGICAL INVESTIGATION. 15 



The predominant Revolutions have consisted in the 

 elevation of the submarine stratified rocks; but, in one 

 case, possibly in more, the revolution has been a de- 

 pression of rocks beneath the water. 



The interior of the Earth contains a permanent 

 source of heat, competent to the powers of fusion 

 and expansion. 



A certain portion of it is permanently fluid. 



It contains, or has contained, cavities. 



It consists of matter heavier than any known rocks. 



It approximates to the figure which would be pro- 

 duced by its diurnal revolution were it a fluid. 



With respect to the FUTURE, it is inferred that the 

 present actions are tending to produce a new condition, 

 analogous to that which is just past. 



The duty and purpose of the imperfect investiga- 

 tion, the only one yet in our power, is to examine the 

 classes of Objects and Actions, to indicate the infe- 

 rences, and, lastly, to describe the remaining Objects 

 which belong to Geology, as a branch of Natural 

 History ; or as an Art, of which some comprise or 

 repeat necessary proofs, others add superfluous ones, 

 and a third set are as yet incapable of classification 

 for the purposes of the Science. 



