GRANITES OF NORTH CAROLINA 387 



and muscovite when present in very subordinate amount. In tex- 

 ture, variation is from even-granular to porphyritic; and in structure 

 from massive to schistose. As a rule, some shade of gray prevails, 

 though pink is largely characteristic of certain areas. The Plateau 

 granites are described under the following belts: The Northeastern 

 Carohna Granite Belt, the Main Granite Belt, and the Western 

 Carolina Gneiss and Granite Belt. 



THE NORTHEASTERN CAROLINA GRANITE BELT. 



This area comprises a part or the whole of five counties located in 

 the extreme northeast part of the Piedmont region, extending north- 

 ward from Raleigh. With but few exceptions, the granites of this 

 belt are partially schistose in structure. The characterizing accessory, 

 biotite, is variable in quantity; imparting accordingly either a light 

 or a dark gray color to the rock. In places the feldspars are of a 

 pronounced pinkish hue and with the subordinate amount of biotite 

 present, the rock assumes more or less of a mixed pinkish-gray color. 

 The granites are usually even-granular in texture, though the porphy- 

 ritic tendency is somewhat emphasized in places. They do not differ 

 essentially in mineralogy, although hand specimens from different 

 areas in the belt may bear no resemblance to each other. 



LITHOLOGICAL CHARACTERS. 



Two areas, differing somewhat widely in the hand specimens, but 

 which may be regarded as representative of the granites of the belt as 

 a whole, are selected for description, in order to make clear the general 

 characters of the rocks as a whole. These are the Raleigh area in 

 Wake county and the Greystone area in Vance county. 



The Raleigh area.— -Studied in the quarries opened within the 

 eastern limits of the city of Raleigh, the rock is a fine even-textured, 

 medium-gray, biotite granite-gneiss, completely interlaced by inter- 

 secting pegmatites. The principal minerals are quartz, orthoclase, 

 microcline, acid plagioclase near oligoclase, brown biotite, muscovite, 

 zircon, apatite, chlorite, and epidote. Quartz is of the usual kind, and 

 is often intergrown with feldspar in micrographic structure, clearly 

 indicating that its period of formation began before that of the feld- 

 spar closed. In addition, it occurs with other minerals, especially 



