Art. VII.] Watson, Virgilina Copper District. 127 



applied to many areas of greatly altered massive and schistose 

 rocks along the Atlantic Coast and Lake Superior regions, 

 shown to have been derived from an original basic eruptive rock 

 type, has equal application to the existing rocks of the Vir- 

 gilina district. 



3. The rocks are pre-Cambrian in age and represent an 

 area of ancient volcanics similar to others described as occur- 

 ring along the Atlantic Coast region from eastern Canada to 

 Georgia and Alabama and in the Lake Superior region. 



4. The rocks are cut by numerous approximately parallel 

 quartz veins which contain workable copper deposits. The 

 veins have been described as true fissure veins, and the ore is 

 glance and bornite, without chalcopyrite and pyrite. 



