Granite of Aberdeenshire. 39 



terms, granitic greenstonCf and granitic basalt ; denominations , 

 which, while they indicate the geological connexions of these 

 substances, are also explanatory of their mineral characters ; 

 and of the relation which, in this respect, they bear to the 

 corresponding rocks of the trap family. It remains for geo- 

 logists to adopt or reject this expedient as they may see right. 



In thus terminating this account of these very interesting 

 varieties of granite, I may be allowed to add, that their history 

 offers a very useful lesson to those geologists who are either 

 content with the first view of things, or who are always ready 

 to determine respecting the appearances which they find, ac- 

 cording to some preconceived opinions, or from the vague 

 and superficial notions derived from other teachers than that 

 great instructor, from a careful examination alone of whose 

 phenomena, truth can be elicited. It will also point out the 

 facility with which the most serious errors may be intro- 

 duced into geological science, by trusting to the mineral cha- 

 racters of rocks, and by neglecting to trace the connexions of 

 such substances with the surrounding masses. If the novelty 

 of the facts which have thus been described, had not rendered 

 the preceding minute details necessary, they would have been 

 still useful to the student, by pointing out the steps which 

 were followed in the investigation, and the nature of the rea- 

 soning from which the conclusions were deduced. If his 

 ambition be to extend the boundaries of geological science, 

 if he is not content to repose in the calm belief that every 

 thing is already known, to see through the eyes of teachers, 

 perhaps less competent than himself, and to describe in a 

 received phraseology, appearances, and analogies, which have 

 no existence but in that language which he has been taught, 

 let him be assured that he must bring to his task, industry, 

 patience, and, above all, an unbiassed mind. Nature will 

 neither long deceive nor disappoint him who is only desirous 

 of truth ; but the book which she opens to his inspection must 

 be studied with care, and, more especially, with a desire to 

 learn. 



