U. S. GEOLOGICAL SURVEY 
ULLETIN NO. 313 PL. 
A. RYAN-PARKER QUARRY ON CROTCH ISLAND. LOOKING SOUTHWEST. 
Showing sheet structure; the thickest sheet measures 25 feet and is split along the rift. 
B. EASTERN SIDE OF MOSQUITO MOUNTAIN, TOWN OF FRANKFORT. LOOKING 
NORTHWEST. 
Showing sheet and dome structure and the erosion of the sheets. 
