ANNIVEKSART ADDRESS OF THE PRESIDENT. Ixxi 



pie ted in a full account of Savoy and the adjoining parts of Pied- 

 mont and Switzerland*, illustrated by an atlas of plates, which unite 

 in an unusual degree the truth of geological sections with the varied 

 outline of charming picturesque mountain-groups. 



The conscientious manner in which our eminent Foreign Correspon- 

 dent has explored and described the elevated region ranged around the 

 towering centre of Mont Blanc is well known to most of our Fellows ; 

 and it is only two years since our lamented friend Mr. Hamilton, 

 in his Presidential Address, took occasion to follow ont at some 

 length one of the most interesting of M. Favre's chapters, as then 

 published in the Bulletin of the Geological Society of France, viz. 

 that on the gradual advance of observation and argument which, 

 after the lapse of many years, established the fact of the presence of 

 the carboniferous formation in the Western Alps. A large portion 

 of the work is, indeed, of a somewhat historical character, since the 

 author, whenever he approaches a subject connected vrith puzzles and 

 theories (and how many of them hang about that classic region !), 

 deems it but just and satisfactory to state fairly the opinions of all 

 previous writers on the same topic, and adds his own objections and 

 propositions with a moderation which suits the character of a philo- 

 sopher who concedes to others the credit of having done their best 

 with the knowledge that was open to them, and compares without 

 prejudice their views with the phenomena which he practically 

 investigates. 



Thus, in his discussion of the cause and effects of the ancient 

 extension of the glaciers, we are supplied with a review of all the 

 more notable hypotheses connected with the ice, and with the part 

 assigned to it in the scooping out of lakes. He combats, as we have 

 seen for years, with many arguments the doctrine of Prof. Eamsay, 

 and is not less opposed to the half-and-half measure of De Mortillet, 

 who, whilst objecting to the competency of glaciers to erode solid 

 rock, claims for them the power of affouillement, or the excavation 

 of all the accumulated debris which he considers to have once filled 

 the lake-basins. M. Favre, noting the position of the lakes on the 

 fringe of the higher Alps, and along a line where physical action on 

 a grand scale has dislocated, contorted, and inverted the strata, 

 connects their formation with the structure of the rock-masses ad- 

 joining, although he allows that the direction of the main lines of 

 valley has doubtless aided in the determination of their position, 

 and that it is impossible to deny that the valleys, after their forma- 

 tion, have been cleared out (deblayees) and enlarged by currents 

 and glaciers. 



Among the most interesting of his chapters are those on the 

 Aiguilles Eouges, and on Mont Blanc itself, with a review of the 

 numerous and often very divergent opinions promulgated by succes- 

 sive geologists who have examined the peculiar structure of these 

 masses. Beginning with De Saussure, we have a long list of ob- 

 servers who are satisfied that the crystalline schists on the flanks of 



* Recherches geologiques dans les parties de la Savoie, du Piemont et de la 

 Suisse voisines du Mont Blanc. 3 vols. 8vo, with an Atlas. Geneva, 1867. 



