ELISHA MITCHELL SCIENTIFIC SOCIETY. 77 



77/e Eastern Granite Belts. — Granitic rocks are abun- 

 dant over considerable areas in the midland and Piedmont 

 counties, and especially in the former. One of these 

 important areas may be called, as a matter of convenience, 

 the Raleigh granite belt; which, in a general way, may be 

 described as enclosed by lines drawn from Gaston to Smith- 

 field, thence to a point midway between Raleigh and Gary, 

 and thence a little east of north to the Virginia line. This 

 belt occupies a considerable part of Wake, including the 

 region about Raleigh, of Franklin, and practically the 

 whole of Warren and Vance counties. The principal 

 rocks of this belt are light-colored gray, comparatively 

 fine-grained, granite and gneiss; on the whole a fairly good 

 material for road construction. The rocks vary in com- 

 position and in appearance at different localities, but are 

 fairly uniform in character over considerable areas. In 

 some places the black or biotite mica is largely wanting, 

 and the rock assumes a whitish feldspathic character; at 

 other points the mica becomes abundant, and the rock 

 assumes a dark gray color. In places the mica is so abun- 

 dant that the gneiss becomes somewhat schistose, or 

 laminated, and in this condition crushes easily, hence 

 should not be used on the roads. Dykes of trap rock are 

 occasionally met with, and these should be used in prefer- 

 ence to the gneiss and granite wherever accessible. 



The somewhat isolated patches of granite lying east of 

 this belt in Halifax, Nash, Edgecombe and Wilson coun- 

 ties have already been referred to. 



West of the Raleigh belt there is another granite area 

 of limited extent which occupies the extreme north-eastern 

 portion of Durham count}' and the larger part of Granville 

 county. This may be called the Oxford granite belt. The 

 rocks of this area resemble to some extent those of the 

 Raleigh belt, but there is a larger proportion of syenitic 

 and trap rocks, which make excellent road material. 



