Ixii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May IpOI. 



THE EVOLUTION OF PETROLOGICAL IDEAS. 



Introduction. 



The nineteenth century, whose obsequies we have so recently cele- 

 brated, was born in what has been aptly termed by Prof. Zittel, our 

 latest historian, the heroic age of geology. Geological Societies 

 and Geological Surveys did not then exist. Cooperative work was 

 unknown ; but a few individuals, of great power and originality, 

 were laying the foundations of our science on a firm basis of 

 accurate observation. Pallas had recently carried out his remark- 

 able researches in Eastern Russia, and had noted the extraordinary 

 abundance of the remains of the mammoth, rhinoceros, and bison 

 in the superficial deposits of the Siberian plains. De Saussure had 

 climbed Mont Blanc, and published his unrivalled descriptions of 

 Alpine scenery and Alpine structure. Werner was still acting as 

 an exponent of the science which he had done so much to foster, and 

 had fired his two most illustrious pupils, L. von Buch and Humboldt, 

 with that enthusiasm for natural knowledge which was destined to 

 produce such glorious results. Hutton had just passed away, after 

 giving to the world his Theory of the Earth, the main features of 

 which form the basis of modern geology. Smith and Cuvier, both 

 born in the same year (1769), were in the prime of life, and actively 

 engaged in those researches which placed stratigraphical geology on 

 a secure foundation. These are some of the heroes of our science. 



The early history of geology is mainly a record of fantastic 

 speculations ; but in the heroic age it was beginning to be recog- 

 nized that no solid advance could be made, except on a basis of 

 carefully observed fact. A reaction against the wild speculations 

 of the seventeenth and the greater portion of the eighteenth 

 centuries had set in, and this led, among other things, to the 

 foundation of our Society — the parent of all such societies — in 

 1807. 



That it was necessary to put a curb on the unbridled licence of 

 geological speculation, and to emphasize the importance of diligence 

 and accuracy in the observation of facts, will be admitted by all 

 students of the history of our science ; but it is well to remember 

 that there is a scientific, as well as an unscientific, use of the 

 imagination. The chief glory of science is, not that it produces an 

 amelioration of the conditions under which we live, but that it 



