130 
THE GRANITES OF MAINE. 
biotite scales up to two-tenths inch. It consists, in descending order 
of abundance, of a pinkish-buff potash feldspar (chiefly orthoclase 
with some microcline), smoky quartz, milk-white soda-lime feldspar 
(oligoclase), and black mica (biotite). together with accessory mag- 
netite, zircon, and apatite. The orthoclase here and there contains 
irregular areas of carbonate, is intergrown with a plagioclase, or 
68° 50' 
Deadm^n Hero 
Ledge 
Heron Neck 
Ledge 
68 50 
/2 
2 miles 
Fig. 
Contour interval 20feet 
Map showing location of quarries in Fox Islands. (From Vinalhaven sheet 
Topographical Atlas of the United states. I', s. Geol. Survey.) 
' 
rimmed with oligoclase. The oligoclase is partially altered to kaolin 
and a white mica. Pyrite i^ found by the quarrymen in rare and 
minute particle-, and molybdenite occurs occasionally in half-inch 
scales. Mr. E. C. Sullivan, of the United States Geological Survey 
finds that this granite contains O.IK34 per cent of 0O 2 (carbon diox- 
