16 Observations on the Geology 



firmly on each other, as if by art. Sometimes they occur on 

 the summit of a hill ; in other instances, they are found com- 

 pletely insulated in a plain. 



From all the circumstances connected with these masses, I 

 think we must conclude, that at present they continue to oc- 

 cupy their original positions ; that they are the slight remains 

 of strata which have been gradually worn down all around 

 them; and that they now stand as monuments of what the 

 depth and nature of these strata formerly were. This con- 

 clusion is as legitimate as that the strata on the opposite coasts 

 of England and France were once continuous, deduced from 

 the circumstances of their corresponding in their nature, rela- 

 tive position, and direction. In order to show more clearly 

 on what grounds I rest the above conclusion, I will consider 

 the subject a little more in detail. We often observe a hill 

 composed of successive strata or lamellae, the most superficial 

 of which are more or less detached and broken up ; that round 

 its base are large accumulations of debris and detached frag- 

 ments ; and that on its summit are three or four masses resting 

 firmly on one another, with their surfaces accurately adapted, 

 except perhaps at their edges, where they have been affected 

 by the weather. Now as we have here ocular proofs that a 

 number of strata (which formerly belonged to this hill) have 

 been detached and worn down ; and as it would almost amount 

 to an absurdity to suppose that the masses on the summit have 

 been conveyed from a distance, and placed there with their 

 surfaces accurately corresponding, we must conclude that the 

 hill was formerly much higher than at present ; and that while 

 a number of its strata have been gradually worn down and 

 swept from its surface, the masses at its summit (which at one 

 time formed part of these strata) have remained steadfast in 

 their original situations, probably from their being more du- 

 rable, or from their horizontal position. It is very evident 

 how this must happen, when it is recollected how the lamellae 

 of the granite are broken down and separated from those be- 

 neath. They split in various directions, and in this manner 

 form a number of separate masses, which slide down the sides 

 of the hill. Now, it is clear, that the part of the lamellae on 

 the summit has every chance of remaining stationary, for it 

 rests horizontal!}'; and while all the detached pieces around it 

 slide down into the neighbouring valleys, it will maintain its 

 situation. When the next bed is exposed to the atmosphere, 

 and becomes detached from that beneath, of course the part 

 on the summit immediately under the fragment which remained 

 stationary in the first instance, has every chance of continuing 

 in its situation ; and thus in the course of time the appearance 



above 



