GRANITE. 85 



give, there are, nevertheless, cases where we may still 

 be at a loss which term to apply justly to a particular 

 mass, as there are others where one superior to the 

 secondary strata may really be a granite. If a rock, 

 with the mineralogical characters of granite, in this 

 position, should be connected with one of similar,, or 

 even of other characters, inferior to the primary strata, 

 it must be considered as a granite, because its charac- 

 ter is decided by this portion. If a granitic rock be 

 connected, on the contrary, with a mass having the 

 geological position and mineral characters of trap, as 

 is the case in Sky, it would be pronounced a trap rock. 

 Should it, lastly, betray neither connexion, we shall 

 still pronounce it a trap, from its position, though it 

 may actually possess connexions with an inferior gra- 

 nitic mass which is invisible or inaccessible, and be 

 thus a real granite. In a reverse manner, should there 

 occur a mass having that deep connexion which all 

 tmstratified rocks must possess, and of which the por- 

 tions superincumbent on the secondary strata had dis- 

 appeared, while the rest remained, it is evident that it 

 must be ranked with granite, according to the adopted 

 rule. This would be the decision of every one, were 

 its mineral characters granitic ; though it might ac- 

 tually be of later date than the latest strata, and still, 

 perhaps, preserving some connexions, to prove its true 

 nature. If its mineral characters were those of a trap 

 rock, if it were even a basalt, 1 have shown that it 

 may still be connected with true granite, and fairly en- 

 titled to that name. Thus, even under this definition, 

 we may decide wrong respecting the real nature of 

 some given instance of these rocks, because their ori- 

 gin is really the same : and hence, whatever prevailing 

 distinctions there may be, both in their mineralogical 

 characters and their positions, the only veal ones arc 



