THE EARLIEST STRATA MELTED Ul&amp;gt;. 353 



ten, contained incompletely-fused clots of sedimentary 

 strata. Kor is this all. Fifty years ago, it was thought 

 that all granitic rocks were primitive, or existed before 

 any sedimentary strata ; but it is now &quot; no easy task to 

 point out a single mass of granite dcmonstrably more an 

 cient than all the known fossiliferous deposits.&quot; 



In brief, accumulated evidence clearly shows, that by 

 contact with, or proximity to, the molten matter of the 

 Earth s nucleus, all beds of sediment arc liable to be 

 actually melted, or partially fused, or so heated as tc 

 agglutinate their particles ; and that according to the tem 

 perature they have been raised to, and the circumstances 

 under which they cool, they assume the forms of granite, 

 porphyry, trap, gneiss, or rock otherwise altered. Further, 

 it is manifest that though strata of various ages have been 

 thus changed, yet that the most ancient strata have been 

 so changed to the greatest extent : both because they 

 have habitually lain nearer to the centre of igneous agency; 

 and because they have been for a longer period liable to 

 the effects of this agency. Whence it follows, that sedi 

 mentary strata passing a certain antiquity, are unlikely to 

 be found in an unmetamorphosed state ; and that strata 

 much earlier than those are certain to have been melted 

 up. Thus if, throughout a past of indefinite duration, 

 there had been at work those aqueous and igneous agen 

 cies which we see still at work, the state of the Earth s 

 crust might be just what we find it. We have no evidence 

 which puts a limit to the period throughout which this for 

 mation and destruction of strata has been going on. For 

 aught the facts prove, it may have been going on for ten 

 times the period measured by our whole series of sedimen 

 tary deposits. 



Besides having, in the present appearances of the 

 Earth s crust, no data for tixing a commencement to these 

 processes besides finding that the evidence permits us to 



