PROGRESS OF PHYSICAL GEOLOGY. 585 



ascribing the phenomena of the earth's surface mainly to aqueou? 

 agency ; the other Plutonian or Vulcanian, because it employed the 

 force of subterraneous fire as its principal machinery. The circumstance 

 which is most worthy of notice in these remarkable essays is, the endeavor 

 to give, by means of such materials as the authors possessed, a com- 

 plete and simple account of all the facts of the earth's history. The 

 Saxon professor, proceeding on the examination of a small district in 

 Germany, maintained the existence of a chaotic fluid, from which a 

 series of universal formations had been precipitated, the position of the 

 strata being broken up by the falling in of subterraneous cavities, 

 in the intervals between these depositions. The Scotch philosopher, 

 who had observed in England and Scotland, thought himself justified 

 in declaring that the existing causes were sufficient to spread new strata 

 on the bottom of the ocean, and that they are consolidated, elevated, 

 and fractured by volcanic heat, so as to give rise to new continents. 



It will hardly be now denied that all that is to remain as permanent 

 science in each of these systems must be proved by the examination of 

 many cases and limited by many conditions and circumstances. Theo- 

 ries so wide and simple, were consistent only with a comparatively scanty 

 collection of facts, and belong to the early stage of geological knowledge. 

 In the progress of the science, the " theory" of each part of the earth 

 must come out of the examination of that part, combined with all that 

 is well established, concerning all the rest ; and a general theory must 

 result from the comparison of all such partial theoretical views. Any 

 attempt to snatch it before its time must fail ; and therefore we may 

 venture at present to designate general theories, like those of Hutton 

 and Werner, as premature. 



This, indeed, is the sentiment of most of the good geologists of the 

 present clay. The time for such general systems, and for the fierce 

 \vars to which the opposition of such generalities gives rise, is probably 

 now past for ever; and geology will not again witness such a contro 

 versy as that of the AVernerian and Huttonian schools. 



As when two black clouds 



With heaven's artillery fraught, come rattling on 



Over the Caspian : then stand front to front, 



Hovering a space, till winds the signal blow 



To join their dark encounter in mid-air. 



So frowned the mighty combatants, that hell 



Grew darker at their frown ; so matched they stood : 



For never but once more was either like 



To meet so great a foe. 



