264 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



craters regarded by him simply as eruptive orifices. The 

 alleged differences resolved themselves into a question of 

 comparative dimensions, and these could be explained by the 

 varying intensity of the explosive convulsions. 



The French Government had sent Constant Prevost, in 

 August 1831, to Pantellaria, in order to study the newly- 

 formed Graham's Island, or lie Julia, as the French 

 Expedition called it. The island vanished in three months, 

 and Prevost was one of the few favoured individuals who 

 had succeeded in visiting and making drawings of it. 

 After fulfilling this commission, he travelled through Sicily, 

 climbed Etna, made a stay in the Lipari Islands, and 

 finally met Hoffmann and Escher von der Linth in Naples. 

 Excursions made in the company of these geologists to 

 Vesuvius and the Phlegrrean fields brought Prevost's 

 memorable tour to a conclusion. Several accounts of his 

 journeys were sent by Prevost to the Academy of Sciences and 

 the Geological Society of ^Paris. 



Meantime, in Paris, Elie de Beaumont (1829-30) had 

 discussed the Elevation-Crater theory in various publications, 

 and had given it strong support ; and when Prevost in his 

 first report on the Island of Julia to the Academy ventured to 

 doubt the theory, and in September 1832, in a second report, 

 went so far as to openly deny the existence of elevation- 

 craters in any volcanic district visited by him, he aroused the 

 displeasure of all the leading members of the Academy. Only 

 the venerable Cordier, who had seen the Canary Isles, 

 expressed agreement with him. In the December of that year 

 Prevost won a valuable ally in Virlet, who proved that the 

 Santorin group, which had hitherto been included amongst 

 elevation-craters, consisted wholly of ejected material. 



In the following years controversy became as keen in the 

 discussion of Buch's theory as it had been in Werner's time 

 over the discussion of the volcanic or aqueous origin of basalt. 

 Annoyed by the attacks on his favourite theory, Buch 

 undertook, in the autumn of 1834, another journey to Italy 

 along with Link, Elie de Beaumont, and Dufrenoy. New 

 evidences were collected, and his views were afterwards 

 pronounced even more firmly. " Craters of Elevation are," he 

 wrote, "remnants of a powerful manifestation of energy from 

 the earth's interior, which is capable of uplifting large islands 

 many square miles in breadth to a considerable elevation. 



