450  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
The  constituents  of  this  slate,  arranged  in  the  order  of  their  abundance,  appear  to  be 
muscovite,  quartz,  chlorite,  pyrite,  and  graphite,  with  accessory  tourmaline,  zircon,  and 
rutile. 
This  slate  at  Pleasant  Pond,  the  nearest  important  topographic  feature,  represents  a 
different  quality  of  black  slate  from  either  the  Brownville  or  the  Monson  slate,  having 
nearly  as  much  luster  and  nearly  as  fine  a  cleavage  as  the  former,  yet  without  its  abundance 
of  magnetite,  and  being  without  the  dull  and  roughish  surface  of  the  Monson  slate.  It 
would  prove  suitable  either  for  roofing  or  mill-stock  purposes. 
Another  ledge  of  similar  slate  has  been  exposed  by  trenching,  about  a  third  of  a  mile 
away,  near  the  road  and  Mr.  Hill's  house,  but  the  slate  here  shows  some  false  cleavage,  at 
leasl  a!  the  .siiri'a'  c  Should  thai  feature  continue  into  the  mass  the  slate  would  have  little 
or  no  commercial  value.     This  feature  was  not  characteristic  of  the  Holly  Brook  outcrop. 
