BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 13, PP. 353-376, PLS. 54-56 NOVEMBER 18, 1902 



COPPER-BEARING ROCKS OF VIRGILINA COPPER DISTRICT, 

 VIRGINIA AND NORTH CAROLINA* 



BY THOMAS LEONARD WATSON 



{Presented before the Society January 2, 1902} 



CONTENTS 



Page 



Introduction , 353 



Previous work 354 



General field characters and occurrence 357 



Petrography 359 



Macroscopic descriptions 359 



Microscopy of the rocks 360 



Chemical analyses 363 



Evidences of eruptive character 367 



Field evidence 367 



Microscopical evidence 368 



Chemical evidence. 369 



Comparison with other areas 369 



Ore deposits of the district 372 



Weathering 374 



Age relations 375 



Conclusions . 370 



Introduction 



Some time was spent during the month of August, 1901, in a field 

 examination of the Virgilina copper district, and the specimens of the 

 rocks and ores collected were subsequently studied in the laboratory. 

 Study was principally confined, both in the field and laboratory, to the 

 rocks of the area, to determine their nature and origin. The ores were 

 given only secondary consideration. 



The rocks have been designated slates by the earlier workers, which, 

 according to present usage, would imply a metamorphosed sediment. 



* The author is under special obligations to Professor J. Morgan Clements, of the University of 

 Wisconsin, for kindly reading and criticising this paper in manuscript, and he is indebted to 

 Mr W. H. Pannebaker, of Virgilina, for the photographs illustrating it. 



LII— Bom. Geol. Soc. Am., Vot,. 13, 1901 (353) 



