LAKE  FORK  MINING  AREA,  COLORADO.  29 
and  the  shaft  is  full  of  water.  Development,  however,  is  known  to 
have  been  carried  to  a  depth  of  160  or  170  feet,  with  an  easterly 
drift  of  about  65  feet  and  one  to  the  west  of  30  or  40  feet.  The 
rocks  in  the  vicinity  are  dark  porphyritic  flows  and  tine  tuffs,  and 
the  material  on  the  dump  is  largely  the  same,  but  its  identity  is 
veiled  by  extensive  mineralization.  Deformation  has  produced  a 
fissure  trending  approximately  east  and  west,  which  may  be 
observed  at  the  surface  and  which  it  is  believed  the  shaft  and  work- 
ings follow.  Ore  is  said  to  have  been  taken  from  this  fissure.  It 
was  of  low  grade,  however,  being  valuable  for  copper,  but  containing 
excessive  amounts  of  iron.  Specimens  collected  from  the  dump, 
moreover,  show  the  country  rock  to  be  greatly  altered  and  silicified 
and  also  penetrated  by  pyrite.  The  vein  material  in  these  speci- 
mens contains  chiefly  chalcopyrite  with  pyrite  and  small  amounts 
of  galena,  quartz  and  rhodochrosite  being  the  gangre  minerals.  Of 
course  this  does  not  preclude  larger  amounts  of  valuable  ore  else- 
where in  the  vein,  but  the  ore  heretofore  found  was  probably  not 
valuable  enough  for  profitable  exploitation  against  a  heavy  flow  of 
water. 
The  Napoleon  shaft  is  located  on  the  south  bank  of  Lake  Fork, 
nearly  opposite  the  Champion  shaft.  It  also  is  full  of  water  and 
abandoned.  It  is  reported  to  have  been  sunk  75  feet  on  an  east- 
west  vein.  This  vein  at  the  surface  cuts  the  igneous  complex  of 
flows  and  tuffs  which  form  both  the  valley  at  this  point  and  the 
country  rock  of  probably  the  whole  shaft.  Ore  of  a  good  type, 
chiefly  gray  copper,  is  known  to  have  been  taken  from  this  vein  and 
shipped,  but  operations  were  discontinued  because  of  water. 
The  Seward  County  property  lies  on  the  north  side  of  the  valley, 
just  east  of  the  Champion  shaft.  The  mine  is  entirely  abandoned 
and  very  little  is  known  concerning  its  history.  The  claim  seems 
to  have  been  opened  by  short  shafts  and  prospect  tunnels,  and  it 
is  reported  vaguely  that  some  gray  copper  and  chalcopyrite  ores 
were  shipped  years  ago.  The  country  rock  is  similar  to  that  at 
the  Champion,  and  the  workings  appear  to  have  followed  zones  of 
silification  and  pyritization  probably  connected  with  fissuring. 
The  great  Ohio  mine  is  a  mile  and  a  half  east  of  Whitecross,  on  the 
east  side  of  Lake  Fork,  between  Cooper  and  Silver  creeks.  At  the 
time  of  visit  this  property  was  being  more  actively  developed  than 
any  other  in  the  vicinity.  Work  was  progressing  in  a  200-foot  tunnel 
which  intersects  an  incline  shaft  from  the  surface  about  100  feet  long. 
A  new  shaft  was  also  in  progress  a  short  distance  east  of  the  tunnel. 
The  rock  near  the  workings  is  commonly  the  quartz-bearing  rhyolite 
mentioned  as  intruding  and  covering  the  fragment al  complex.  This 
proves  to  be  also  the  rock  underground.  It  has  suffered  considerable 
deformation  through  fissuring  along  approximately  north-south  lines, 
