OF THE ROCK FORMATIONS. 335 



unstratified rocks may have been variously metamor- 

 phosed. It matters not whether sve admit the nebular 

 hypothesis or not, a time must have been when all these 

 bodies which now form the mass of this globe existed in 

 the most simple state. We have already shown that 

 very remarkable changes in external character and in 

 chemical relations are induced, in the same simple 

 element, by its having been exposed to some peculiar 

 and different conditions ; and already have we speculated 

 on the probability that the advance of science will enable 

 us to reduce the numerous elements we now reckon, to 

 two or three. It is, therefore, by no means an irrational 

 thought (which must, however, be held in the light of a 

 pure conjecture), to suppose that at the beginning a 

 mighty mass of matter, in the most attenuated state, was 

 produced in space, and was gradually, under the in- 

 fluence of gravitation, of cohesive force, and of chemical 

 aggregation, moulded into the form of a sphere. 

 Ascending to the utmost refinement of physics, we may 

 suppose that this mass was of one uniform character, 

 and that it became in dissimilar parts its surfaces and 

 towards its centre differently constituted, under the 

 influences of the same powers which we now find pro- 

 ducing, out of the same body, charcoal and the diamond, 

 and creating the multitudinous forms of organized 

 creations. These conditions being established, and 

 carried to an extent of which, as yet, science has 

 afforded us no evidence, chemical intermixture may have 

 taken place, and a new series of compounds have been 

 formed, which, by again combining, gave rise to another 

 and more complex class of bodies. 



The foundation of the superficial crust of the earth 

 appears to be formed of a class of rocks which have 

 resulted from the slow cooling of an immense mass of 

 heated matter. These rocks have been called igneous ; 

 but are now more generally termed Plutonic (such as 

 granites, syenites, &c.) Immediately above these, we 



