142 ON THE REVOLUTIONS 



Dr Hutton and Mr Playfair, as I have already said, deny 

 the necessity of introducing such an agent, since the circum- 

 stances, as they conceive, might have been produced by the 

 usual action of rivers. But this simple view seems to be ex- 

 cluded, when we consider both the magnitude and the posi- 

 tions of these blocks. Their size, in some cases, amounts, as 

 in the valley of Monetier upon Saleve, to 1200 cubic feet, and 

 in the case of those on the Coteau de Boisy, to 2250, and even 

 to 10,296 cubic feet, which is the measure of the block called 

 Pierre ti Martin. 



To move a mass of granite of even fifty or sixty cubic feet, 

 and to carry it a few yards, would require the utmost efforts of 

 the Rhone or the Arve, as they flow near Geneva, in their 

 highest floods, but that such blocks could be conveyed by one 

 of them along its whole course, is contrary, I conceive, to all 

 experience, and still more when we consider that these rivers 

 are divided at their source from beneath the Glaciers into for- 

 ty oi* fifty small streams. Yet from the Glaciers, these blocks 

 must have come ; and when we take into account the magni- 

 tude of some of the granitic masses, it is clear that the task is 

 beyond the power of any river that flows on the surface of the 

 earth ; nay, it seems more than water, under any predicament, 

 could accomplish, and more than could be expected from the 

 Debacle itself, however extravagant its magnitude may appear: 

 but we shall again return to the subject, and shew in what 

 manner this difficulty may be explained. 



These stones do not lie merely in the beds of rivers, but oc- 

 cur all over the country, and on the summits of mountains, 

 where rivers could least be conceived to have flowed ; nor are 

 they confined to that side of the country, or to the side of the 

 lake of Geneva which lies next the Alps ; for we find them in 

 particular on the face of Jura, which fronts the central ridge 



and 



