356 T. L. WATSON VIKGILINA COFPEK DISTRICT 



and schists, . . . lying conformably between slate walls . . ." 

 He further mentions small crystals of magnetite occurring in gray mica- 

 ceous schist coated with malachite. 



Nitze and Hanna* mention in " Gold Deposits of North Carolina " 

 the principal copper mines in the copper belt, giving assays of the ores 

 and describing in some detail the topography and general geologic fea- 

 tures. They designate the rock as schist. 



Pages 37 to 43 of the same report describe the occurrence of ancient 

 acid volcanics found in the same belt, but directly southwest of the Vir- 

 gilina area. The scattered areas lie principally in Chatham and Orange 

 counties, within short distances of Kaleigh and Chapel Hill. The close 

 resemblance of certain onesinftructure and composition to the rhyolites 

 of South Mountain in Pennsylvania is noted. The localities were vis- 

 ited by Professor George H. Williams, in company with Professor J. A. 

 Holmes, in the summer of 1893, and afterward discussed in the Journal 

 of Geology for 1894 by Williams. f They are referred to as pre-Cambrian 

 in age, and are suggested as probably being contemporaneous with the 

 somewhat analogous rocks of the South mountain, in Maryland and 

 Pennsylvania. 



In describing the Carolina Gold Belt area, situated in the central 

 Piedmont region and crossing the central part of the state in a south- 

 westerly direction, Nitze and Wilkens J again refer to the kinds and dis- 

 tribution of the ancient volcanic rocks. Their description follows : § 



"The volcanic rocks occupy irregular patches along the eastern border of the 

 belt, in close proximity to the western edges of the Jura-Trias basins. They com- 

 prise both acid and basic types. The acid rocks are generally devitrified to such 

 an extent that their real character is no longer recognizable to the naked eye, and 

 they appear as ordinary cherts or hornstones, although flow structure is at times 

 still discernible. Microscopic examination shows them to belong .to the class of 

 rhyolites and quartz porphyries. They are sometimes sheared into schists, as for 

 instance at the Haile mine, South Carolina. The basic types are dark green in 

 color and perhaps pyroxenic in composition; they are sometimes massive por- 

 phyrites, but more generally sheared into schists. The pyroclastic breccias con- 

 sist of angular fragments of the acid rhyolites and porphyries in a basic matrix. 

 The age of these ancient volcanics is believed to be pre-Cambrian. They seem to 

 be analogous to, and probably contemporaneous with, similar rocks of the South 

 mountain in Maryland and Pennsylvania, and other points along the Atlantic 

 coast." 



Professor George H. Williams || published in 1894 a very important 



*Gold Deposits of North Carolina, N. C. Geol. Survey, Bulletin no. 3, 1896, p. 52. 



f Journal of Geology, 1894, vol. ii, pp. 1-31. 



t Gold Mining in North Carolina, et cetera, N. C. Geol. Survey, Bulletin No. 10, 1897, pp. 15, 16. 



§ Ibid., p. 16. 



|| Journal of Geology, 1894, vol. il, pp. 1-31. 



