PETROLOGY OF SOUTH CAROLINA GRANITES 741 
Carolina, 8.62 per cent. anorthite and 35.11 per cent. albite, cor- 
responding to Ab,An,; Georgia, 13.34 per cent. anorthite and 40. 35 
per cent. albite, corresponding to Ab,An,; North Carolina, 7.23 per 
cent. anorthite and 42.44 per cent. albite, corresponding to Ab,An,. 
The ratio of potash to soda-lime feldspar in the Winnsboro dark 
blue-gray type of granite is: South Carolina, 1:1.7; Georgia, 1:1.9; 
North Carolina, 1:2.6. 
The gray granites from Columbia, Pacolet, and near Carlisle in 
Union County, S. C., vary from the type of the Winnsboro blue- 
Fic. 3.—Bowlder outcrop of the Winnsboro Granite Corporation’s light-gray 
granite at Rion, Fairfield County, S. C. 
gray granite chiefly in lighter color and coarser crystallization. Hand 
specimens of the granite from the different localities contrast strongly 
with each other in many cases, but they are essentially similar in 
mineral and chemical composition. ) 
The Greenwood—Cold Point types.—The granites at Quarry in 
Greenwood County, and at Cold Point farther north in Lancaster 
County, though essentially similar mineralogically, are of two varieties 
which bear but slight resemblance to each other in the hand speci- 
mens. The granite at Quarry is more coarsely crystalline with 
bluish opalescent quartz, while the Cold Point variety is more finely 
crystalline and the quartz varies from colorless to moderately dark 
smoky in color. The feldspars in both varieties (gray granites) are 
