In the vicinity of Mont Blanc, 193 



dissever them stratigraphically. Nay, we even there see the Num- 

 mulitic rocks, which in parts of the chain are clearly superimposed 

 upon fossiliferous Chalk, pass under all these older rocks, whether 

 Secondary or Carboniferous ! 



Now, one of the great merits of M, Favre is, that he has patiently 

 and diligently followed out many of such folds and inversions in 

 the heart of these mountains, and has b^n able to assign to them 

 their relative places ; but still there are many lofty portions of the 

 chain respecting which great uncertainty still exists as to the relative 

 age of some rocks which most geologists consider to be metamorphic. 



In conclusion, we recommend the work of M. Favre as a capital 

 study for those nimble climbers of the higher parts of the chain, who, 

 ignoring nearly everything but the superficial accumulations of snow, 

 ice, and glaciers, go aloft to catch light and shadows, air-effects, and 

 cloud-views. Without such preliminary study they can have little or 

 no conception of the physical and mental toil which the geologist has 

 undergone in unravelling the complicated strata of which the peaked, 

 the gnarled, and the rounded mountain-masses are respectively formed 

 — complications, indeed, repeated in breaks, twistings, and crumplings, 

 most of which were successively brought about in ages long before a 

 flake of snow fell upon the rising Alps. And upon this point, 

 too, the glacierist, as well as the geologist, will find in the first 

 volume of M. Favre's book many excellent and original data illus- 

 trative of the more recent periods at which the glaciers have shot 

 off much detrital matter, and of the relations of such debris to the 

 existing valleys and river-courses. 



No one can doubt that the snows and glaciers of the Alps, in 

 melting and moving since the earliest glacial period, have deepened 

 valleys on highly inclined planes, have lowered peaks and abraded 

 surfaces of considerable magnitude. But he who, exaggerating the 

 power of these comparatively recent causes, says, in his atmospheric 

 and glacierist pride, that they have carved out the great valleys and 

 have determined the main outlines of the chain, overlooks the 

 indubitable effects of the grand subterranean forces which truly 

 gave in very early ages a leading impress to the broadly marked 

 features of mountain and valley — features which, however since 

 modified by atmospheric agencies, have never been obliterated, and 

 which are as eternal as the snows and glaciers of the Alps are, in 

 a broad geological sense, casual and ephemeral.^ 



In short, the glacierist who has not worked out the evidences of 

 these great subterranean changes, and reasons upon present forms 

 and outlines of nature, must first learn his lesson respecting internal 

 and original structures, before he can pretend to reason on this broad 

 and complicated question. To all such persons we commend the 



^ It is in the first volume of the work of M. Favre, that the reader will find how 

 he eliminates from each other the various superficial deposits, beginning witb what he 

 calls the accumulations of the plain and the deposits of the Rhone and its leading 

 affluents. He then describes the Quaternary Deposits, consisting of recent alluvium, 

 terrace deposits with remains of extinct animals, glacier detritus, and still older marine 

 deposits, with lignite. 



