18 THEORY OF THE EARTH. 



times their rocks, suddenly approaching from each 

 side, form transverse dikes, over which the waters 

 tumble in cataracts. The dissevered strata, while 

 they shew on one side their edges perpendicular- 

 ly raised, on the other present large portions of 

 their surface lying obliquely ; they do not corres- 

 pond in height, but those which, on one side, 

 form the summit of the cliff, often dip underneath 

 on the other, and are no longer visible. 



Yet, amidst all this confusion, distinguished 

 naturalists have been able to demonstrate, that 

 there still reigns a certain order, and that those 

 immense deposits, broken and overturned though 

 they be, observe a regular succession with regard 

 to each other, which is nearly the same in all the 

 great mountain chains. According to them, Gra- 

 nite, of which the central ridges of the greater 

 number of these chains consist, and which thus 

 surmounts every other rock, is also the rock which 

 is found deepest in the solid crust of the globe, 

 It is the most ancient of those which we have 

 found means of examining in the place assigned 

 them by nature ; and we inquire not at present, 

 whether it owes its origin to a general fluid, which 

 formerly held every thing in solution, or may have 

 been the first consolidated by the cooling of a 

 great mass in fusion, or even in a state of vapour *. 



* The conjecture of the Marquis de la Place, that the 



