ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxiij 



disposition of tertiary lacustrine and volcanic strata, and those on the 

 volcanic strata of the neighbourhood of Naples, where he distinguished 

 between the trachytes and pumice of the Phlegraean fields and the 

 ancient lavas of Somma, as also between those ancient lavas and the 

 recent lavas of Vesuvius, are proofs of great sagacity and judgment. 

 It is to be observed, however, that he shared with M. Elie de Beau- 

 mont and M. Dumont in the belief of the theory of uplifted craters, 

 and endeavoured to explain the mathematical laws of those forces 

 which have produced the elevation of volcanic cones, — a task for 

 which his mathematical education at the Ecole Polytechnique had 

 eminently qualified him : indeed such an education seems indispen- 

 sable for all those who intend to deal with the phenomena of physical 

 geology. His work, again, on the age and composition of the forma- 

 tions of the "West of France is one of much ability, his principal object 

 having been to determine the geological position of the principal iron- 

 mines and of the rocks generally of the Eastern Pyrenees. 



His work on Mineralogy is very extensive, and is one of great 

 merit : it explains not only the physical and chemical properties of 

 minerals, but also their geological relations ; and a very good judge 

 has particularly extolled his critical acumen and his fidelity, remark- 

 ing that " it is much more common in these times, to find mineralo- 

 gists ready, on very slight grounds, to establish new and ill-defined 

 species, than disposed to efface from the nomenclature substances 

 which have no right to figure there. It is, in fact, easy to assume 

 the merit of having given a name to a substance without having 

 taken the trouble to study it sufficiently for an accurate definition ; 

 but it is a long, difficult, and ungrateful task to demonstrate the errors 

 of others." How true is this remark, and how applicable to the ex- 

 amination and determination of organic fossils ! 



So highly were the talents of M. Dufrenoy appreciated, that he 

 was consulted on many difficult subjects extraneous to his ordinary 

 duties, such as the purification of the Sologne and the management 

 of the mineral waters of Vichy and Plombieres ; and it may be asserted 

 that he was during his whole life the enthusiastic friend of science, 

 and the successful promoter of every useful application of scientific 

 knowledge. 



M. Alcide D'Orbignt, Professor of Palaeontology at the Museum 

 of Natural History in the Jardin des Plantes, was remarkable for 

 the vast magnitude, as well as for the interesting character of his 

 palaeontological works, intended as they were to embrace the whole 

 field of geology in Erance, and, of course, comparatively to notice the 

 relations of the ancient inhabitants of all portions of the earth whilst 

 describing those of his native country. M. D'Orbigny was born at 

 Couezon (Loire Inferieure), and has been in succession Travelling 

 Naturalist for the Museum of Natural History, Secretary of the 

 Natural History Society, Member of the Central Commission of the 

 Geographical Society, Assistant of M. Cordier in the Geological 

 Course, and latterly placed in the chair of Palaeontology which had 



