LECTUKE II 



The rise of volcanic geology Desmarest Rise of geological 

 travel Pallas, De Saussure. 



THE leading position taken by France in the investigation 

 of the history of the earth was well maintained in the later 

 decades of last century. Geology as a distinct science did 

 not yet exist. The study of rocks and their contents was 

 known as mineralogy, which as a pursuit, often of economic 

 value, had been in vogue for centuries. The idea that 

 beyond the mere variety of its mineral contents, the crust 

 of the earth contained a record of the earth's evolution, for 

 many ages before the advent of man, only very slowly took 

 definite shape. Buffon partly realized it ; Guettard had a 

 fuller perception of its nature, though he failed to observe 

 proofs of a long succession of changes earlier than the 

 present condition of the surface. 



One of the most valuable parts of Guettard's work was 

 his recognition of the existence of volcanic rocks in regions 

 far removed from any active volcano. We have seen that 

 he was led to this important deduction by a train of 

 observation and inference, and that although he never 

 worked out the subject in detail, the credit of the first 

 discovery, denied to him in his lifetime and after it, must 

 in common fairness be assigned to him. 



