102 
THE GRANITES OF MAINE. 
Ryan-Parker Construction Company, Park Row building, 13-21 
Park Row, New York. 
The granite (specimen 20, h) is a biotite granite of lavender, 
medium-gray color and coarse, even-grained texture, consisting, in 
descending order of abundance, of very light lavender-colored potash 
feldspar (orthoclase and microcline). smoky quartz, milk-white soda- 
lime feldspar (oligoclase), and a little mica (biotite), rarely a plate 
Contour interval 20 feet 
I^n.. 15. — Map showing location of quarries aboul Stonington, Mr. (Reduced from Deed 
Isle Sheet, Topographic Atlas U. S.. V. s. Geol. Survey.) 
of muscovite, together with accessory magnetite, titanite, zircon, and 
pyrite, partially altered to limonite. The potash feldspars measure 
up to 1 inch and many of them are twinned and intergrown with a 
plagioclase. The biotite plates do not exceed 0.1 inch across. The 
oligoclase is generally much altered to a white mica and kaolin. 
Mr. E. C. Sullivan, of the United States Geological Survey, deter- 
mined the presence in this granite of 0.011 per cent of C0 2 (carbon 
dioxide) and of 0.08 per cent of CaO (lime) and a little MgO (mag- 
