634 HISTORY OF GEOLOGY. 



sought for, from a wish to arrive at such conclu- 

 sions; but it has flowed spontaneously from the 

 manner in which we have had to introduce geology 

 into our classification of the sciences : and this clas- 

 sification was framed from an unbiassed considera- 

 tion of the general analogies and guiding ideas of 

 the various portions of our knowledge. Such re- 

 marks as we have made may on this account be 

 considered more worthy of attention. 



But such a train of thought must be pursued 

 with caution. Although it may not be possible to 

 arrive at a right conviction respecting the origin of 

 the world, without having recourse to other than 

 physical considerations, and to other than geological 

 evidence ; yet extraneous considerations, and ex- 

 traneous evidence, respecting the nature of the 

 beginning of things, must never be allowed to in- 

 fluence our physics or our geology. Our geological 

 dynamics, like our astronomical dynamics, may be 

 inadequate to carry us back to an origin of that 

 state of things, of which it explains the progress : 

 but this deficiency must be supplied, not by adding 

 supernatural to natural geological dynamics, but by 

 accepting, in their proper place, the views supplied 

 by a portion of knowledge of a different character 

 and order. If we include in theology the specula- 

 tions to which we have recourse for this purpose, 

 we must exclude them from geology. The two 

 sciences may conspire, not by having any part in 

 common ; but because, though widely diverse in 



