OF THE EARTH'S SURFACE. 209 



of which is evinced, as has been shewn, by the concurrence of 

 a three-fold set of facts, surrounding us in this neighbourhood. 

 1. The distribution of loose matters in tails and ridges, on 

 this side of the Island, and in knolls on the West. 2. The 

 grooves and scoopings, and obtuse-angled ridges, occurring 

 on the surface of rocks of every description ; and, lastly, the 

 scratches and other minute features of abrasion, which are 

 found to accompany the large features, where the rock has 

 been protected from injury. All these events have been 

 shewn to arise, as natural consequences, out of the Huttonian 

 Theory. 



As another consequence of these events, I have also brought 

 forward the formation of valleys of all sorts. I have imputed 

 the detachment of mountains, and the formation of islands, as 

 well as of promontories and arms of the sea, to circumstances 

 which could not fail to take place in the forcible elevation of 

 stiff and frangible masses, performed by a succession of local 

 efforts from beneath, urged by irresistible power *. 



I have furnished a theory of the formation of lakes, which 

 does not seem hitherto to have been accomplished in a satis- 

 factory manner, by any other hypothesis. One class, belong- 



Vol. VII. D d ing 



* Since the first part of this paper was printed, a very familiar circumstance 

 has presented itself, which affords a clear illustration of this great natural ope- 

 ration. When a mason is preparing common lime for building, he lays the burnt 

 limestone in a heap, and throws water upon it ; after this, some time elapses be- 

 fore any action is visible, before the lime, as it is said, begins to fall ; in this in- 

 terval the sand, which is to be mixed with the lime, is thrown upon the heap, so 

 as to cover it completely, and the surface is made smooth and uniform by re- 

 peated blows of the flat of a spade. Soon after this, a heave takes place from 

 within ; the lime swelling, raises up the sand, and divides it by numberless rents, 

 which becoming wider and wider upwards, as the heave advances, a representa- 

 tion in miniature is produced, of an alpine district. 



