184  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull.  225. 
VEINS  AND  ORES. 
Yems. Three  fairly  well-defined  veins  have  been  opened,  named 
the  Wardlow,  the  Finley,  and  the  Magruder,  which  are  approximately 
parallel,  having  a  general  direction  of  N.  25°  to  40°  E.  They  vary  in 
width,  and  represent  the  more  completely  silicified  portions  of  the 
sheared  and  crushed  schists.  They  are  composed  of  fine,  granular, 
saccharoidal  quartz,  interlaced  with  stringers  of  broken,  massive  quartz. 
Like  the  country  rock  proper,  they  are  throughout  thinly  laminated 
or  schistose  in  structure.  The  ore  is  distributed  through  the  veins  in 
the  form  of  stringers,  irregular  bunches,  or  nests,  and  as  large  and 
small  disseminated  grains  and  particles.  The  ore  occurrence  as  dis- 
seminated grains  or  particles  closely  resembles  that  of  the  inclosing 
rock,  except  that  in  the  veins  the  mineral  particles  are  in  a  more  local- 
ized and  concentrated  form.  The  ore  distributed  through  the  sur- 
rounding rock,  particularly  the  pyrite,  is  invariably  in  the  form  of 
large  and  small  cubical  crystals.  The  central  portions  of  the  veins  are 
characteristic  and  are  sharply  differentiated  from  the  inclosing  rock, 
while  the  outer  portions  next  to  the  wall  appear  less  easy  of  differenti- 
ation from  the  schists  in  many  places.  Lenses  of  varying  sizes,  com- 
posed of  schists  similarly  silicified  and  mineralized  as  the  true  veins, 
occur  between  the  veins  and  in  some  instances  afford  equally  as  good 
ore.  These  lenses  may  be  spaced  at  wide  intervals  or  they  may  occur 
close  together. 
Ores. — The  ores  consist  chiefly  of  chalcopyrite,  galena,  sphalerite, 
and  pyrite.  A  little  native  copper  occurs  in  the  Wardlow  and  Finley 
veins;  and  in  places  traces  of  tenorite  (black  oxide  of  copper)  are 
observed.  The  veins  are  remarkably  free  from  carbonates;  only  traces 
of  malachite  (green  carbonate)  occur,  and  this  has  probably  formed 
in  large  part  at  least  since  the  opening  of  the  veins. 
More  complete  silicification  is  invariably  accompanied  b}^  increase  of 
chalcopyrite  and  gold.  Galena  when  present  is  always  associated  with 
chalcopyrite  and  both  are  argentiferous.  The 'galena  is  invariably 
concentrated  in  the  form  of  stringers  and  bunches,  but  has  not  been 
observed  disseminated  through  the  veinstuff  in  grains  and  crystals  like 
the  other  sulphides.  Pyrite  is  found  in  all  types  of  the  rocks;  it  occurs 
as  stringers  in  the  veins,  and  as  disseminated  large  and  small  crystals 
and  grains  in  the  schists  and  dikes.  As  a  rule  the  wall  is  more  heavily 
impregnated  with  pyrite  than  the  rock  at  some  distance  from  the  vein, 
and  it  may  be  present  in  larger  or  smaller  quantity  in  the  veins  than 
in  the  wall  rock.  When  galena  is  present  pyrite  almost  entirely  dis- 
appears or  is  reduced  to  a  minimum. 
In  general  sphalerite  follows  the  hornblende-schist  dikes.  It  is  found 
in  largest  quantity  in  the  Magruder  vein,  with  only  traces  noted  in  the 
A\  ardlow  vem  and  none  in  the  Finley.     Very  little  galena  occurs  in 
