NORTHERN"  IDAHO  AND  NORTHWESTERN  MONTANA.      45 
tains  at  Prospect  Creek.  It  continues  across  into  the  Cabinet  Range  at  the  heads  of  Fisher 
River  and  Vermilion,  Libby,  and  Callahan  creeks,  and  so  northward  into  the  Loop  Moun- 
tains at  Sylvanite.  The  Pend  Oreille  mineral  area  may  be  said  to  mark  its  western  flank. 
At  different  periods  many  small  mining  camps  have  flourished  in  this  general  region. 
Much  development  work  has  been  done,  but  at  present  only  one  property  is  making  regular 
shipments.  Sufficient  low-grade  ore  has  been  opened  on  several  claims  to  encourage 
further  work. 
CHARACTER  OF  DEPOSITS. 
Nearly  all  the  metalliferous  deposits  observed  in  the  region  are  veins  which  have  been 
formed  by  filling  fissures  and  replacing  their  walls.  In  some  instances  after  the  vein  was 
filled  movement  again  took  place  which  slickensided  the  vein  material.  There  are  a  few 
contact  deposits  of  minor  importance. 
It  may  be  noted  that  the  base  ore  lies  comparatively  close  to  the  surface  in  this  region, 
and  there  is  very  little  secondary  enrichment  or  concentration-  of  the  leached-out  surface 
values  at  depth.  This  may  be  accounted  for  by  the  rapid  erosion  which  the  surface 
rocks  have  undergone,  particularly  where  glaciation  has  prevailed. 
The  only  noteworthy  nonmetalliferous  mineral  resources  are  some  limestone  beds  from 
which  lime  is  being  manufactured. 
DESCRIPTION  OF  DISTRICTS. 
For  convenience  the  economic  deposits  will  be  described  by  districts  in  the  following 
order:  Pine  Creek,  Lake  Pend  Oreille,  Troy,  Sylvanite,  Snowshoe,  Cabinet,  and  Prospect 
Creek. 
PINE  CREEK. 
General  features. — Pine  Creek  is  about  6  miles  west  of  the  Bunker  Hill  and  Sullivan  and 
the  Last  Chance  mines.  It  flows  in  a  northerly  direction  into  Coeur  d'Alene  River  and 
drains  a  large  wooded  basin. 
The  country  rock  is  Prichard  slate  and  the  veins  are  fissures  which  have  generally  been 
formed  by  faulting  and  which  often  have  their  walls  partly  replaced  by  vein  material. 
The  vein  filling  is  white  quartz  and  crushed  country  rock,  the  whole  somewhat  iron  stained. 
The  ore  is  a  silver-bearing  galena  associated  with  zinc  and  some  siderite  and  pyrite.  The 
silver-lead  values  are  low,  and  transportation  charges  are  so  high  at  present  that  mining 
for  zinc,  though  the  ore  sometimes  runs  up  to  20  or  30  per  cent,  is  not  profitable.  The 
weathered  zone  of  these  veins  was  fairly  rich  in  silver  and  lead  carbonates  to  a  slight  depth, 
but  the  base  ore  was  soon  reached  and  development  work  was  then  usually  suspended. 
Although  much  exploration  work  had  been  done  in  the  district  and  considerable  bodies 
of  low-grade  silver-lead-zinc  ore  found,  very  little  mining  activity  was  evident  at  the  time 
of  visit. 
Mines  and  properties. — The  Anderson  group,  3  miles  from  the  mouth  of  Pine  Creek, 
has  a  few  tons  of  rich-looking  ore  on  the  dump.  A  60-foot  adit  and  20-foot  winze  are  the 
extent  of  development  work. 
At  the  King  property,  a  mile  south  of  the  Anderson  property,  a  few  tons  of  ore  have 
been  extracted  from  an  85-foot  adit. 
The  Douglas,  6  miles  south  of  the  King,  has  had  a  considerable  amount  of  development 
work  done.  Three  hundred  tons  of  ore  are  on  the  dump  and  about  10,000  tons  in  sight. 
The  ore  is  peculiar  in  that  it  seems  to  be  a  fine-grained  galena,  carrying,  it  is  reported, 
almost  30  per  cent  of  zinc. 
The  Surprise,  on  another  branch  of  Pine  Creek,  is  about  2  miles  southeast  of  the  Douglas, 
A  450-foot  crosscut  adit  taps  the  vein  at  considerable  depth.  It  is  said  to  give  an  average 
assay  of  31  per  cent  lead,  30  per  cent  zinc,  and  10  ounces  of  silver  to  the  ton. 
The  Nevada  Stuart  is  just  across  the  creek  from  the  Surprise,  and  is  on  the  same  north- 
west-southeast lead.     A  300-foot  adit  constitutes  the  development  work. 
