U. S. GEOLOGICAL SURVEY 
LETIN NO. 313 PL. 
A. ARCH PRODUCED BY THE BURSTING OF A THIN SHEET OF GRANITE-GNEISS, 
ROCK CHAPEL HILL ; NEAR LITHONIA, GA. 
Width of arch, 14 feet; height, 9 inches. Photograph by G. K. Gilbert, United States Geological 
Survey. 
B. LOWER EDGE OF SCHIST INCLUSION IN GRANITE ON WORKING FACE OF 
FREEPORT QUARRY. 
Showing contact of schist and granite; also schist fragments more or less completely detached from the 
inclusion. The black streak on the granite is ferruginous stain from the biotite schist. 
