﻿ANNIVERSARY ADDRESS OF THE PRESIDENT, 



SIR CHARLES LYELL. 



Gentlemen, — The list of our Foreign Members has for many years 

 been limited by the Council to the number of fifty, and death has 

 deprived us since our last Anniversary of three of the most distin- 

 guished names which adorned this list, those of MM. Beudant, De 

 Blainville, and Dubois de Montpereux. 



M. Beudant, a Member of the French Institute and Professor of 

 Mineralogy in the College of France, is best known to us by his work 

 on the Volcanic Mountains of Hungary, entitled ' Voyage Mineralo- 

 gique etGeologique dans laHongrie, pendant 1818/ published in 1822. 

 It contains an excellent classification of the different varieties of tra- 

 chyte, perlite, pitchstone, obsidian, and pumice, together with the 

 opals and other siliceous minerals. His theory, that the lamination 

 of trachyte and obsidian may have been due to the motion of the 

 mass when in a fluid or semi-fluid state, has since been very generally 

 adopted. 



Among his early papers, we find a Memoir read to the Academy of 

 Sciences in 1816, on the possibility of causing fluviatile mollusks to 

 live in salt water, and marine mollusks to exist in fresh water. The 

 mixture of marine and freshwater shells observed in a tertiary sand- 

 stone, called the gres de Beauchamp, near Paris, excited his curiosity 

 on this subject, and he enjoyed facilities of making illustrative experi- 

 ments and observations when appointed Professor in the College at 

 Marseilles, near which the brackish water at the mouths of rivers 

 entering the Mediterranean is inhabited both by fluviatile and marine 

 species. 



In 1817 M. Beudant published a paper on the Phenomena of 



