204 UNIVERSITY OF VIRGINIA PUBLICATIONS 



shows the outHne of the mountain. On the crest of the ridge, a fairly pro- 

 nounced axial depression or sag is noted bounded at either end by higher 

 elevations or peaks which slope away somewha.t gradually toward the north- 

 east and southwest until merged into the plateau surface. 



Geology of the surrounding areas. The rocks of the region are strongly 

 foliated metamorphosed crystallmes of two dominant types,* variable 

 micaceous schists and gneisses. To the north and south of Graves Moun- 

 tain the schists vary from biotitic to sericitic, and in places are highly 

 quartzitic, feldspar being only sparingly developed and is frequently absent. 

 The gneiss of Little River basin in the vicinity of the gold mines in northern 

 McDuffie County is of granitic composition, usually carrying biotite as the 

 dark silicate mineral, although hornblende has been noted. The dominant 

 rock of the gold belt on Little River is mica schist which encloses the gold 

 veins of milky white quartz containing the sulphides, pyrite, chalcopyrite, 

 and galena. The gneiss of this belt is derived from an original granite and 

 Jones suggests that because of chemical similarity the schists are also of 

 probable igneous origin. Analyses of these rocks are given in columns IV, 

 V, and VI of the table of analyses on page 205. 



The geology of the Seminole copper mine and immediate vicinity, three 

 and one-half miles north of Graves Mountain, is more varied, several igneous 

 rock types occurring that have not been observed in the Little River belt on 

 the south . In addition to the mica schists, schistose quartz-albite porphyry 

 occurs, composed of a fine-grained groundmass of quartz and plagioclase 

 feldspar intimately intergroma and exhibiting spherulitic structure, through 

 which are distributed phenocrysts of opalescent quartz, some albite and 



* During the field season of 1911, Mr. Otto Veatch of the Georgia Geological Survey 

 made a brief reconnaissance over much of Lincoln Countj' and contiguous parts of 

 the counties to the south. In a personal communication to the senior author, Mr. 

 Veatch states that the belt of metamorphic sedimentary rocks in which Graves 

 Mountain is located seems to extend from the Savannah River in Lincoln County 

 westward to Graves Mountain and Adasburg a short distance south in Wilkes County ; 

 thence southwestward through the northern part of McDuffie and Warren counties. 

 A generalized section extending from Lincolnton southeastward to Augusta, a dis- 

 tance of nearly forty miles, prepared by Veatch shows the principal rock types of the 

 area to be schists, slates, and quartzites with an extensive area of granite containing 

 intrusions of serpentine, peridotite and diorite, occupying the central portion of the 

 section. The metamorphic sediments on the northwest side of the granite area dip 

 steeply toward the northwest becoming vertical with slight southeastward inclina- 

 tion near and at Lincolnton. From the southeast margin of the granite to Au- 

 gusta the metamorphic sediments are steeply inclined to the southeast. As indicated 

 in Veatch's section the metamorphic sediments dip steeply away from the granite 

 on the northweist and southeast sides. 



