382 THOMAS L. WATSON 



exposures no definite statement can be made regarding whether the 

 granite-gneisses are the more schistose transitional portions of a more 

 massive granite stock. The completely schistose structure has 

 nowhere been positively traced into the more massive granites, though 

 this may be the true relation. That the areas of schistose granites 

 mentioned above are the metamorphosed equivalents of the massive 

 granites apparently admits of no reasonable doubt. 



As pointed out in my study of the Georgia granites,' the exact 

 relationship is an important one as bearing on the question of the 

 relative age of these rocks. If the schistose rocks (granite-gneisses) 

 cannot be traced into granites of more massive structure, but the two 

 are separate and distinct, then clearly two periods of intrusion must 

 be admitted, separated by an interval of intense pressure-metamor- 

 phism, which resulted in inducing the secondary schistose structure 

 in the earlier massive granites, represented, if the postulate is correct, 

 by the present granite-gneisses. If, on the other hand, the two rep- 

 resent phases of the same rock-mass in which the action of dynamic 

 forces has been greater in some parts of the massif than in others, 

 then the same age must be assigned them. As elsewhere shown in 

 my study of the Georgia granites, the first condition apparently 

 obtained, and the granites are not all of the same age, but at least 

 two separate periods of intrusion of nearly identical material are 

 indicated. * 



GRANITES OF THE COASTAL PLAIN REGION. 



GENERAL CHARACTERS. 



The line marking the contact between the Coastal Plain and the 

 Piedmont Plateau formations in North Carohna is a very irregular 

 one. It enters North Carohna from Virginia a short distance east of 

 the Warren county line and crosses the state in a general southwest 

 direction, passing into South Carolina a short distance southwest of 

 Wadesboro. To the east of this line are the loose unconsolidated 

 formations of the Coastal Plain. 



In many places near the contact of the Coastal Plain formations 

 with the rocks of the Piedmont Plateau, but falHng well within the 



I "Granites and Gneisses of Georgia," Bulletin No. Q-A, Geological Survey of 

 Georgia, 1902. 



