221 



which are more or less difficult to distinguish 

 without referring to their order in geological 

 position. 



Among the unstratified rocks of the primary 

 class, granite, when composed of quartz, mica, 

 and felspar, is always to be distinguished, as no 

 corresponding rock has yet been found in the 

 unstratified members of the secondary division. 

 But where granite contains hornblende, there is 

 sometimes ground for doubt ; as similar com- 

 pounds occur with the syenite of the overlying 

 family. 



In a similar manner, rocks compounded of 

 hornblende and felspar, which prevail among 

 the members of the latter division, are sometimes 

 found associated with granite, and therefore ne- 

 cessarily to be ranked in the primary class ; 

 however differing in their mineral characters 

 from the prevailing rocks known by this general 

 term. These cases are however rare, and will 

 seldom produce much practical inconvenience ; 

 as they will chiefly excite the attention of those 

 geologists whose experience will enable them to 

 assign their true geological situations, and whose 



