GRANITES OF NORTH CAROLINA 381 



evidence supporting tliis belief may be summarized as follows: the 

 sharpness of contact between the porphyritic and the non-porphyritic 

 granite ; the prevaihng coarser texture of the porphyritic granite along 

 the line of contact than that of the non-porphyritic rock ; the banding 

 in places along the contact; inclusions of the porphyritic granite in 

 the even-grained granite; and the occurrence of probable apophyses 

 of the fine-grained granite penetrating the porphyritic granite. 



GRANITE-GNEISS. 



True granite-gneisses are found in many places over the state, but 

 perhaps the most typical areas are: (i) the unreduced residual locally 

 known as Rockyface Mountain in Alexander county; (2) the area 

 near Balfour station in Henderson county; and (3) the area on the 

 Josey-Bogers places, three miles southwest of Faith in Rowan county. 

 Wherever studied, the granite-gneisses are biotite-bearing, fine to 

 medium texture, and closely resemble the massive granites in all 

 essentials except that of schistose structure. Some effects of pressure- 

 metamorphism are indicated either megascopically or microscopically 

 in the granites of most of the areas studied. Granites of complete 

 schistose structure were not definitely traced in any single area into 

 entirely massive ones, although this may be the real condition in many 

 cases. Lack of sufficient exposures of the rocks renders this uncertain 

 in the North Carolir^ areas. 



RELATIONS BETWEEN THE THREE TYPES OF GRANITE. 



Enough description has been detailed above under the even- 

 granular, porphyritic, and schistose granite to make fairly clear, so 

 far as the field study is possible, the relations between the three tex- 

 turally and structurally unlike granites here distinguished. It seems 

 reasonably certain, so far as I have been able to interpret the field 

 relations, that the porphyritic and non-porphyritic granites represent, 

 with one or two possible exceptions different facies of the same granite 

 mass. The principal exception noted above is that of the Mooresville 

 area in Iredell county, where the normal granite is intrusive in the 

 porphyritic granite. 



The exact relations of the schistose (granite-gneisses) to the even- 

 granular massive granites are less clear, and for lack of adequate 



