56 M. Ch. Martins on the 



portance of a great revolution, and its theatre may be said 

 to include a considerable portion of the two hemispheres. If 

 human genius should one day explain the cause of this gla- 

 cial cataclysm, it will throw the brightest light on the last 

 phase of the geological history of the globe, — on the myste- 

 rious epoch which preceded the appearance of Man on the 

 surface of the earth, — and on that universal Deluge, of which 

 traces are found in the traditions of nations in Europe, Asia, 

 and the two Americas. The intimate relation which connects 

 these two phenomena cannot be denied, for they are attested 

 at once by reason and observation. Yet we do not propose^ 

 to pursue the study of glacial phenomena in all the countries 

 where they have been attended to ; we confine ourselves to 

 the study of them among the Alps, where the facts, well 

 known and appreciated, may be verified every year by nume- 

 rous travellers. 



Have the glaciers of Switzerland and Savoy always been 

 confined within their present limits, or did they formerly ex- 

 tend into the great plains which lie around the chain of the 

 Alps \ Such is the problem, when reduced to a simple form. 

 My object is to explain the facts on which the advocates of 

 the ancient extension of glaciers rest the argument. In order 

 to establish their views, they have to combat, among philo- 

 sophers, convictions of old standing, resting on the most un- 

 exceptionable authorities in geology ; among men of the 

 world, the testimony of biblical tradition, and that of all the 

 senses, which revolt against the idea of considering these 

 plains, now so fertile and animated, as having been buried 

 during long periods under an immense sheet of snow and ice. 

 Both parties have a right to demand numerous and positive 

 proofs. These proofs exist ; but, before examining them, it 

 is necessary to possess some knowledge of existing glaciers; 

 for the method followed by geologists, to whom we are in- 

 debted for the results which we are about to lay before the 

 reader, has always been that introduced into science by M. 

 Constant Prevost, and wliich may be briefly expressed in this 



Brongniart, Sefstroem, Keilhau, Boethling, Siljestroem, Daubree, Murchison, 

 Verneuil, and Dui-ocher, in Scandinavia; Hitchcock and Darwin, in America. 



