The American Geologist, Vol. XXVII. 
Plate XVIII. 
Pl.\te XVIII. Figure i. Photomicrograph of the Oglesby d.\kk- 
BLUE Granite. One mile south of Oglesby^ Elbert county, 
Georgia. Crossed nicols — X74. 
Plate XVIII. Figure 2. Photomicrogr.\ph of the Echol's Mill 
light-gray Granite. Eleven miles northeast of Lexington, 
Oglethorpe county^ Georgia. Crossed nicols X74. 
