weed.]  NOTES    ON    THE    COPPER   MINES    OF    VERMONT.  195 
this  incline  was  315  feet  long,  the  depth  was  1,800  feet  in  1886.  and 
3,386  feet  in  1903. 
Eedkiction  works.—  This  property  was  equipped  with  smelting-  works 
earl}7  in  its  history,  and  was  for  many  years  regarded  as  a  model  in 
this  respect.  In  1885  there  were  24  brick  furnaces,  of  a  type  origi- 
nating here,  and  called  the  Vershire  type.  Rapid  advances  in  metal- 
lurgical treatment  soon  made  the  plant  antiquated,  and  it  was  remodeled 
by  Cazin  in  1888-89  and  a  100-ton  concentrator  built  at  an  expense  of 
$53,000.  The  plant  erected  at  that  time  is  estimated  to  have  cost 
$700,000. 
After  the  purchase  of  the  property  by  the  present  owners  various 
changes  were  made  and  a  year's  work  done.  The  result  was  not  satis- 
factory, for  although  equipped  with  modern  water-jacket  blast  fur- 
naces, reverberatories,  and  a  Bessemer  plant,  the  treatment  of  raw 
sulphides  resulted  in  low-grade  mattes  (14  per  cent)  and  the  re-treat- 
ment of  material  so  increased  the  cost  as  to  render  the  work  unprofit- 
able. The  ore  was  found  to  be  somewhat  lower  grade  than  had  been 
expected  and  very  siliceous,  so  that  barren  fluxes  had  to  be  obtained. 
The  ore  deposit. — The  ore  deposit  is  composed  of  lenticular  masses, 
averaging  100  feet  in  horizontal  extent,  10  feet  in  thickness,  and  100 
to  300  feet  along  the  dip.  The  ore  bodies  appear  to  be  conformable 
to  the  foliation  of  the  inclosing  schists,  and  therefore  simulate  bedded 
deposits.  The  strike  is  north-south;  the  dip  24°  E.  The  ore  consists 
of  magnetic  pyrite  and  chalcopyrite,  with  some  pyrite  and  sphalerite, 
with  intergrowths  of  quartz  and  actinolite;  in  the  leaner  ores  are 
biotite,  calcite,  garnet,  and  other  characteristic  inetamorphic  minerals. 
The  chalcopyrite  is  partly  of  the  same  age  as  the  pyrrhotite,  but  the 
larger  masses  of  this  mineral  fill  fractures  in  the  pyrrhotite  and 
represent  the  filling  of  later  fractures. 
A  study  of  the  thin  sections  of  the  ore  made  for  me  by  T.  L.  Wat- 
son shows  conclusively  that  the  sulphides  are  of  later  formation  than 
the  silicates.  The  lean  ore  consists  of  quartz,  with  a  mesh  of  horn- 
blende needles,  all  more  or  less  altered.  Actinolite  is  present  in  small 
amount.  Zoisite,  so  common  in  the  analogous  ores  of  Tennessee,  is 
entirely  absent.  Brown  biotite  mica  is  very  common  in  the  ore- 
forming  tufts  and  groups  of  elongated  shreds.  In  some  samples  much 
of  the  biotite  is  altered  to  brownish  red  rutile.  An  examination  of  the 
ore  on  the  dump  shows  that  while  hornblende  and  biotite  occur  at 
times  together,  that  there  is  a  general  tendency  toward  a  segregation 
of  either  one  or  the  other  mineral. 
The  ores  carry  an  average  of  3  per  cent  copper  as  mined.  They 
contain  the  usual  small  amounts  of  gold  and  silver,  with  a  little  zinc, 
and  are  free  from  arsenic  and  antimon}^.  The  Bessemer  copper  con- 
tains about  13  ounces  of  silver  and  $2  in  gold  per  ton. 
