454 SKETCH TOWARDS A 



gest, whether this also may not reconcile the fre- 

 quent earthy character of serpentine, with that former 

 dependence on heat which I have also proved. 



I need make no new remarks on the decomposition 

 and disintegration of rocks though exposure to water 

 and air: hut having shown that these can separate solid 

 scales from the surfaces of many, I beg to point out 

 the explanation of this as a problem for future geolo- 

 gists ; while I have thus also proved that peculiarities 

 of decomposition do not always depend on concretion- 

 ary structure. And to conclude on this division of the 

 Theory of the Earth, if I may now refer, backwards, 

 to the list of demonstrated facts which proceeded this 

 sketch, it remains to enquire of the present condition 

 of the globe, as far as there is any thing which de- 

 mands to be included in a general theory. And, first, 

 of the alluvial strata. 



The elevation of the secondary strata must have 

 brought up the submarine unconsolidated alluvia also; 

 while further, no such movement could have happened 

 without the production of currents in the ocean. Thus 

 have I explained those alluvia of obscure origin to which 

 hypothetical causes have been assigned, be their cha- 

 racters or places what they may: as this also tends to 

 explain certain traces left on solid rocks. 



These must be the earliest of alluvial matters; but I 

 have proved that partial elevations have occurred since 

 that period; partly through the appearances of the 

 tertiary strata, and partly by the nature of their organic 

 remains. Since these cannot be separated at present, 

 either from the former or among themselves, I can 

 but name them in some probable order; while remark- 

 ing that the elevated substances are either solid or 

 loose, whatever the causes of the consolidation may 

 be. Geology will probably never determine what the 



