Remarks on Dr. Boase's Primary Geology. 545 



than it would otherwise possess. Indeed, without such an intro- 

 duction, the succeeding theoretical discussion would not be generally- 

 understood. 



" It has always been kept in view as an important object, to pre- 

 serve these details as free as possible from all hypotheses : but the 

 language of the science is, in many instances, so engrafted and 

 founded on theoretical speculations, that it could not be always 

 accomplished ; for in some cases, the published descriptions would 

 not admit of translation into less exceptionable language without 

 the risk of perverting the author's meaning, or of incurring the impu- 

 tation of misrepresenting facts. 



" In the arrangement of these details the following order has been 

 adopted : 



*' 1st. A description of the various kinds of granitic rocks, and the 

 modes in which they are associated together. 



" 2nd. Of the primary schistose rocks, under the same relations. 



" 3rd. Of the structure of the primary rocks. 



" 4th. Of the nature of the primary rocks, both granitic and 

 schistose, at their junction with each other. 



" hth. Of the modes in which these rocks are intermixed and con- 

 nected together. 



" 6th. Of the mineral and metalliferous veins by which these 

 rocks are traversed." 



In his 2nd Chapter, the author enters upon a minute des- 

 cription of the granitic rocks of Cornwall, which being in a 

 great measure technical, it would be difficult to make a sum- 

 mary interesting to the general reader. 



The following definition is given of the application of the 

 name : 



" Granite, in the common and original acceptation of the term, 

 denotes a rock composed of felspar, quartz, and mica. It oftentimes 

 contains in addition to these, some other minerals ; but those just 

 enumerated are considered, in the following pages, as essential to true 

 granite ; and if either of them is wanting, the compound may then 

 receive a distinct denomination. These component minerals of 



