EECENT    WORK    ON    NEW    ENGLAND    GRANITES.  359 
Westerly  granites,  the  "white  granite"  of  the  New  England  Granite 
Works,  which  is  really  a  medium  pinkish  gray,  shows  when  thus 
examined  feldspar,  59;  black  mica,  3.85;  very  slightly  smoky  quartz, 
36;  magnetic  iron,  0.75;  white  mica,  0.50.  It  also  shows  that  the 
average  diameter  of  all  the  particles,  including  the  very  fine  particles 
of  magnetic  iron,  is  0.0069  inch,  or  0.175  millimeter;  but  the  coarser 
particles  of  feldspar,  quartz,  and  mica  as  measured  with  the  microm- 
eter range  in  diameter  from  0.015  to  0.439  inch,  or  0.39  to  1.122 
millimeters. 
The  study  of  the  numerous  economic  and  scientific  data  obtained 
at  all  these  quarries  is  not  sufficiently  advanced  to  permit  any  fur- 
ther preliminary  publication. 
The  two  reports  together  will,  it  is  hoped,  constitute  an  important 
contribution  to  an  authoritative  compend  of  the  economic  geology 
of  New  England  granites. 
