ON THE earth's SURFACE. 157 



proposed by M. Wrede, in so far as to consider the granitic 

 blocks as having been made to float, by means of a. mass of ice 

 attached to each. 



A circumstance happened lately in this country which tends 

 to encourage that idea. Upon the coast of the Murray Frith, 

 a large block of stone, four or fiv« feet in diameter, lying with- 

 in high-water mark, and well known as having served to de- 

 note the boundary between two estates, was, during a stormy 

 night in winter, transported to the distance of ninety yards^ 

 and the persons upon the spot were convinced, that this mi- 

 gration v.'as performed by means of a large cake of ice, formed 

 round the stone, and attached to it ; and that the whole had 

 been lifted and carried forward by the rising tide. The course 

 of this stone was marked upon the sand below, by a deep and 

 broad furrow, which remained visible for a long time after- 

 wards, as I have been informed by several members of this So- 

 ciety, who saw it after an interval of more than a year. 



By supposing that an agent of this sort acted in concert with 

 our diluvian wave, the difficulty with regard to the transpor- 

 tation of the granitic blocks, seems to be in a great measure re- 

 moved ; and this explanation happens to be peculiarly appli. 

 cable to the case in point ; the native place of these blocks 

 being covered profusely with ice, in the state best calculated 

 for fulfilling the office here assgned to it. M. de Saussure has 

 given the following clear account of the formation of the Gla- 

 ciers. In any region whose temperature is such that the heat 

 of summer is not sufficiently powerful to melt all the snow of 

 winter, the remaining snow, which, by partial thawing, and sub- 

 sequent freezing, is turned into ice, must accumulate year af- 

 ter year to an unbounded degree, so that the mass must be- 

 come at last so lofty, as to be unable to bear its own weight, 

 and must produce a motion downwards, which will be greatly 



assisted. 



