MODERN GEOLOGY 



the positions in the following manner: 'One sees/ 

 said he, 'upon the slope of an inclined meadow, two 

 of these great bowlders of granite, elevated one upon 

 the other, above the grass at a height of two or three 

 feet, upon a base of limestone rock on which both rest. 

 This base is a continuation of the horizontal strata of 

 the mountain, and is even united with it visibly on its 

 lower face, being cut perpendicularly upon the other 

 sides, and is not larger than the stone which it sup- 

 ports.' But seeing that the entire mountain is 

 composed of the same limestone, De Saussure naturally 

 concluded that it would be absurd to think that it was 

 elevated precisely and only beneath the blocks of 

 granite. But, on the other hand, since he did not 

 know the manner in which these perched stones are 

 deposited in our days by glacial action, he had re- 

 course to another explanation: He supposes that the 

 rock was worn away around its base by the continual 

 erosion of water and air, while the portion of the rock 

 which served as the base for the granite had been pro- 

 tected by it. This explanation, although very in- 

 genious, could no longer be admitted after the re- 

 searches of M. Elie de Beaumont had proved that the 

 action of atmospheric agencies was not by a good deal 

 so destructive as was theretofore supposed. De Saus- 

 sure speaks also of a detached bowlder, situated upon 

 the opposite side of the Tte-Noire, ' which is,' he says, 

 ' of so great a size that one is tempted to believe that it 

 was formed in the place it occupies; and it is called 

 Bdrme russe, because it is worn away beneath in the 

 form of a cave which can afford accommodation for 

 more than thirty persons at a time.'" 4 



153 



