PETROLOGY OF SOUTH CAROLINA GRANITES 733 
a small part of Greenville and Pickens counties, S. C., Keith’ refers 
the Henderson granite to the Archean, the Brevard schists, including 
fine-grained black and dark schists, with lentils of limestone, to the 
Cambrian, and the Whiteside granite doubtfully to post-Cambrian 
age. 
Excepting the Whiteside granite mapped by Keith in the “ Pisgah 
Folio” as of doubtful post-Cambrian age, Paleozoic granites are yet 
unknown in the South. For this reason and because of the absence 
of definite evidence to the contrary, the South Carolina granites are 
provisionally assigned by the writer as pre-Cambrian in age. 
THE GRANITES 
DISTRIBUTION 
Granite occurs in each of the twenty-one counties composing the 
crystalline area described above. During the summer of 1908, 
quarrying was in progress in nine of the twenty-one counties. ‘The 
principal producing areas extended southwestward across the state 
along or near the fall-line in Lancaster, Fairfield, Richland, Lexing- 
ton, and Edgefield counties, and in the extreme northwest portion 
of the state in Pickens County. Both massive (even-granular and 
porphyritic) and foliated (schistose) types of granite are frequent over 
the crystalline area. These are described in detail in the following 
pages under a number of individual types based chiefly on differences 
of physical characters and to a less degree on composition. 
MINERAL COMPOSITION 
The South Carolina granites—mixtures of feldspar, quartz, and 
biotite—correspond closely in mineral composition with the granites 
of the southeast Atlantic states in general. They are prevailingly 
biotite granites. Muscovite, in association with biotite, is a sub- 
ordinate constituent in a part of the granites of Edgefield, Fairfield, 
Oconee, and York counties, and is a principal constituent in a reddish- 
gray granite found near Liberty Hill post-office in Kershaw County. 
Hornblende has been met with in the granite of one locality only, 
namely, one mile south of Winnsboro on the Winnsboro-Rockton 
« Arthur Keith, Geologic Atlas of the United States, ‘Pisgah Folio,’’ No. 147, 
1907, ‘‘ North Carolina—South Carolina.” 
