132 ON THE CHARACTERS AW DISPOSITION 



been surveyed and reduced to a geological map. It 

 would be now easy to solve this problem as far as 

 relates to Britain, as well as to some other European 

 districts ; but a general expression of the extreme 

 disproportion between the stratified and unstratified 

 rocks, is all that can here be necessary. In Britain it 

 may be stated that the whole of the latter, comprising 

 alike trap and granite, do not cover a thousandth part 

 of the superficies of the island. If we examine the 

 flat tracts of Russia and Poland, and of other similar 

 countries, thousands of square miles will be found not 

 containing the least vestige of these rocks. 



Although the unstratified rocks do not necessarily 

 occupy the summits of a country, they are found prin- 

 cipally in mountainous, or at least in hilly regions. 

 In the tracts of an uniform low level, to which I have 

 just alluded, they very rarely exist at all. Thus a 

 connexion is traced between the existence of these 

 rocks and the disposition of the surface ; a connexion, 

 it is true, not very rigid, but sufficient, when com- 

 bined with many other circumstances relating to thenr 

 to be of some value in our reasonings respecting their 

 origin and consequences. 



It is a familiar observation, that granite forms the 

 highest peaks and ridges of the most elevated moun- 

 tains of the globe. The remark is however more 

 common than true : it is certain that it constitutes 

 many of these, but there are numerous mountains in 

 the first class of elevations, that are formed of strati, 

 fied rocks to the summits. Even where granite exists, 

 it often forms only a portion of the highest points ; 

 the sides, even at very great elevations, and many of 

 the ridges and peaks, being still constructed out of the 

 superincumbent strata. In a certain limited sense, it 

 may also be said, that Trap forms the higher summits 



