Art. VII.] Watson, Virgilma Copper District. 99 



ferentiation and classification of the rocks of the Virgilina dis- 

 trict has yet been undertaken. Brief references of a general 

 character dating as far back as the Emmons Survey (1856) are 

 found in numerous reports on economic subjects issued by the 

 North Carolina Geological Survey. Such references as bear 

 directly on the area in question are here reviewed : 



After describing the Gillis copper mine in Person county, 

 North Carolina, the earliest discovered one in the belt. Doctor 

 Emmons^ refers to the rock as follows: "The rock immedi- 

 ately investing the mine is the altered slate belonging to the 

 Taconic system." Emmons first thought the rock was talcose, 

 but later regarded it as argillaceous. 



Professor Kerr* makes no special mention of this individual 

 area in his report on the geology of North Carolina, but in de- 

 fining the "Huronian" rocks of the state he groups the area as 

 the northernmost limit of a belt of Huronian rocks traversing 

 the state in a northeast-southwest direction. Speaking 

 in a general way of the rocks composing the Huronian belt, 

 Kerr mentions the following types: "Quartzite, clay slates, 

 gray, light-colored and drab and greenish." "At some points 

 the quartzites are argillaceous, and at others a few miles west 

 of Smithfield it approaches a fine conglomerate. The clay 

 slates are occasionally slightly hydro-micaceous. " He mentions 

 dikes of diabase and dolerite as being common over parts of 

 Granville county. Professor Kerr refers the rocks of certain 

 parts of Granville and Person counties to the lower Laurentian. 

 He mentions the "characteristic and prevalent rocks as being 

 syenite, dolerite, greenstone, amphibolite, granite, porphyry 

 and trachite. " 



In a geological map of North Carolina, accompanying a 

 report by Kerr and Hanna in 1887, the Person-Granville county 

 area is grouped as the northernmost part of the Huronian.^ A 

 section given at the bottom of the map, extending from the 



^ Geology of the Midland Counties of North Carolina, 1856, p. 344. 

 ' Geology of North Carolina, 1875 ; Vol. I, pp. 123, 124, and 131. 

 ^ Map accompanying " Ores of North Carolina," 1898. 



