Ch. XVI.] TO THE PREVAILING THEORY. 381 



all the phenomena of the primary rocks, or, indeed, of the 

 secondary, can receive thereby a satisfactory solution. As 

 regards the application of this rule to the tertiary rocks, he 

 appears to have been eminently successful ; but when he 

 touches on the department of the science which forms the 

 subject of this work, his speculations seem to us to be as fan- 

 ciful as those of the earlier geologists. The Neptunian spe- 

 culations, originally suggested by the observed effects of 

 aqueous agents, were pushed, he says, beyond the limits of 

 analogy : an observation which seems to apply also to the 

 modern Plutonic theory, since he has admitted that " nothing 

 strictly analogous to the primary rocks can now be seen in 

 the progress of formation on the habitable surface of the earth> 

 nothing, at least, within the range of human observation." * 

 This being the case, we think that, after the numerous objec- 

 tions which have been advanced against this theory, we are 

 justified in our dissent from speculations which are not sup- 

 ported by analogy, and will not account for all the phenomena; 

 and we may, perhaps, be permitted to attempt their explanation 

 in a different manner, and to show how this may be conjoined 

 with the prevailing opinions. 



It has been already stated, that the result of the preceding 

 enquiry has led us to conclude that the primary rocks, both 

 granitic and schistose, are of contemporaneous origin, only 

 differing from each other in their component parts being so 

 aggregated as to produce different kinds of structure. We 

 do not contend that any particular agent, whether fire or 

 water, has formed these rocks ; as it is immaterial to our views, 

 how the fluidity of the mass was originally accomplished, 

 provided its particles had such a degree of mobility as would 

 permit their regular and elective arrangements. But as the 

 general opinion inclines to the adoption of fire as the grand 

 primeval cause which prevailed over all others previous to the 

 consolidation of the earth's crust ; and as it appears to be 



* Principles of Geology, vol. iii. p. 11. 



