OF THE SEA AND LAND. 41 



powerful within its confined range, requires ages to 

 perform on a narrow line of surface. I believe that 

 this is long likely to continue one of the greatest diffi- 

 culties in Geology. 



The decomposition of strata in, situ, and the tedious 

 action of rains, producing a gradual flow of water on 

 the surface, will probably account for many of the 

 denudations which .occupy large spaces without ex- 

 tending to great depths : such as those which occur 

 among the strata of England ; while also, as I believe, 

 they account for many more. To that preparatory 

 cause, however, must be added the usual waste of 

 rocks through atmospheric agencies : and, if I mis- 

 take not, the great denudations of Trap in Scotland 

 can be explained in this simple manner. That it is a 

 great power, though tedious in its effects, I have al- 

 ready said ; and if it be that which has lowered Egg, 

 for example, I know not what it might not effect. 

 Nor do such cases admit of any other ; because the 

 remaining veins, or protruding rocks, of whatever na- 

 ture, are often so slight and feeble that no power ca- 

 pable of removing the surrounding land quickly, could 

 have left them standing. The great vein of Curnbray, 

 formed of transverse columns which the human hand 

 can remove, could not have resisted the least force of 

 water, nor could the Cheese-wring of Cornwall. The 

 power in question is indeed feeble, as the action has 

 been tedious ; but it is never-ending, and it is sure ; 

 as it is the very agent provided for a great Final Cause, 

 the perpetual renovation of Soil. And if we witness 

 it in these cases, so do we in others, where a summit 

 of some harder rock, or even an insulated and casual 

 stone, will often protect a whole cone of feeble land, 

 vthere a neighbouring portion, not thus guarded, is 

 wasted away. Having thus the most absolute demon- 



