Art. VII.] Watson, Virgilina Copper District. 121 



The evidence here adduced from the descriptions of the 

 rocks of the several areas indicates the striking fact that the 

 present altered rock, greenstone, is remarkably similar for the 

 several districts, but when, through chemical and microscopic 

 means, they are traced to the original rock, distinct differentia- 

 tion, such as distinguishes the various basic igneous types from 

 each other, is shown. Moreover, not only is this striking sim- 

 ilarity indicated in the altered rock in each instance, but the 

 processes involved in producing the alteration have been uni- 

 formly alike. The alteration has been one of structural and 

 chemical metamorphism, resulting in the formation of abundant 

 chlorite and epidote and smaller amounts of other secondary 

 minerals and the accompanying secondary schistose structure. 



Ore Deposits of the District.' 

 The deposits of the immediate district are copper, with 

 those of workable iron ore reported from other portions of the 

 same counties. Copper prospecting in the district dates back 

 forty or fifty years. The Gillis copper mine was opened in 

 1856,^ exposing a large body of copper glance. Systematic 

 work is of recent date, however. 



The ore occurs mostly in quartzose veins, and to a limited 

 extent as finely divided particles disseminated through the rocks 

 in places. The workable ore is confined entirely to the veins. 

 The vein stone consists principally of quartz with considerable 

 calcite and epidote mixed locally. The altered country rock, 

 greenstone, is intimately mixed with the quartz and calcite as 

 thin lenses and stringers, which impart, in places, a banded 

 structure to the vein. The included portions of the altered 

 rock vary from mere films and dark streaks in the quartz to a 

 preponderance of the schist with quartz infiltrated between the 

 layers. The quartz is further frequently encased by layers of 

 the schist wrapped around it. 



* For a detailed description of the individual mines and the general features 

 of the belt as a whole, see W. H. Weed, Trans. Amer. Inst. Min. Engrs., 1901, 

 vol. XXX, pp. 449-15O4. An earlier account is given by Geo. B. Hanna in Ore« 

 of North Carolina, 1888, pp. 214-220. 



* Emmons, E., Geol. Survey of North Carolina, 1S56, p. 344. 



