GRANITES OF NORTH CAROLINA 385 



which were derived in part from original igneous rocks. Contacts 

 between the granite and the schists were nowhere observed, but the 

 field evidence clearly suggests that the granite is the younger rock. 



Pegmatite veins, ranging from a fraction of an inch to more than 

 six inches across, composed of pinkish feldspar and quartz, with a 

 very subordinate amount of biotite, penetrate the granite. Nearly 

 all gradations from those veins containing mostly feldspar to those 

 containing mostly quartz occur. In some of the veins the quartz 

 forms a narrow central band in the feldspar. Others still are banded 

 with a fine-textured granite of the same mineral composition as the 

 inclosing rock. Some of these are true veins of segregation; others 

 are less certain of interpretation, mainly because of the lack of expo- 

 sures for examining them. 



Megascopically the rock is somewhat unlike that described above, 

 the Elm City area. It is entirely massive, of medium texture, and 

 gray color. In mineralogy it differs from the Elm City rock in the 

 entire absence of hornblende, and in the presence of only a shght 

 amount of plagioclase. Orthoclase and microcHne have nearly 

 equal distribution. Quartz forms a fine mosaic, occupying distinct 

 areas. Intergrowths of micrographic structure are rather abundantly 

 distributed through the sections in irregular small areas. The 

 accessory minerals are biotite, chlorite, epidote, apatite, zircon, and 

 magnetite. 



The W adeshorO'Rockingham porphyritic granite area. — This is a 

 large area of porphyritic granite lying partly in Anson and partly in 

 Richmond county, near the South Carolina line and to the west of 

 Charlotte. About one mile east of the westernmost exposure of the 

 granite the Triassic sandstones first appear, overlying unconformably 

 the crystalline schists. Between the granites and the sandstones is 

 an area of variable crystalline schists, principally micaceous and 

 quartz schists. Between Rockingham and the easternmost outcrops 

 of the granite the rocks are concealed by Coastal Plain sands and 

 afford no evidence of the nature of the underlying crystallines. In 

 and about the town of Rockingham the principal outcrops indicate a 

 greenstone schist much crushed and fractured, and strongly suggests 

 derivation from an original basic igneous rock. The schists to the 

 east and west of the granite mass must be regarded as older in age 



