Remarks on Dr. Boase's Primary Geology. 561 



in the usual acceptation of the word, only differing from granite in 

 the mode in which their component particles are aggregated to- 

 gether : and, finally, that although the primary slates in structure 

 often resemble rocks of the fossiliferous groups, yet they are not 

 detrital and sedimentary rocks, as we shall attempt to show in a 

 succeeding chapter." 



In the 13th Chapter, the subject considered is, 



" Have the primary schistose rocks been elevated into their present 

 inclined position by Plutonic agency ?" 



The description of apparently elevated strata in various 

 parts of the world is reviewed, also igneous operations now 

 in progress— elevation-craters — changes of level of sea and 

 land — the apparent protrusion of granite in a solid and fluid 

 state — and various other points upon which it is quite impos- 

 sible to give an abstract of the various important and con- 

 flicting evidence collected, but of the nature of which an idea 

 may be formed from the author's concluding inferences. 



" On the grounds detailed in this chapter, we therefore conclude 

 that the inclined position of strata is not an infallible criterion of 

 mechanical elevation ; that this appearance in the primary slates 

 may be more justly attributed to their original structure, and in 

 many of the secondary strata to the same cause conjointly with 

 their deposition on inclined surfaces ; and, that the notion of granite 

 having been protruded through and tilting up the strata, either in 

 a fluid or solid state, does not appear to be countenanced by 

 reference to the known effects of igneous agency ; and, lastly, that 

 the situation of strata adjacent to trap-rocks, the supposed connect- 

 ing link between the granitic rocks, and existing volcanic products, 

 is of too intricate and conflicting a nature to be received as positive 

 evidence of such an occurrence." 



(To be continued. J 



