ORE  DEPOSITS  IN  THE  ST.  JOE  RIVER  BASIN,  IDAHO. « 
By  Arthur  J.  Collier. 
INTRODUCTION. 
The  region  herein  described  lies  south  of  and  adjacent  to  the  Cceur  d'Alene  mining  dis- 
tricts of  northern  Idaho,  which  are  the  most  important  sources  of  argentiferous  lead  ore  in 
the  United  States.  It  comprises  parts  of  30  townships,  mostly  unsurveyed,  included  within 
the  limits  of  the  Northern  Pacific  land  grant.  Though  not  very  remote  from  railroads  and 
populous  mining  towns,  it  is  undeveloped  and  practically  unexplored,  since  it  is  situated 
in  the  heart  of  the  Coeur  d'Alene  Mountains.  For  this  reason  it  has  been  included  within 
the  limits  of  the  proposed  Shoshone  Forest  Reservation.  In  1899,  1900,  and  1901  these 
lands  were  investigated  by  a  United  States  mineral  commission,  appointed  to  examine 
lands  within  the  Northern  Pacific  grant,  and  were  by  that  commission  classified  as  mineral 
lands,  b 
This  classification  being  protested  by  the  Northern  Pacific  Railway,  F.  M.  Goodwin, 
special  agent  of  the  General  Land  Office,  and  the  writer  were  detailed  to  make  an  examina- 
tion of  the  lands  in  question  preparatory  to  a  hearing  ordered  for  October  1,  1905,  at  the 
land  office  in  Cceur  d'Alene,  Idaho.  In  accordance  with  instructions  two  months  were 
spent  in  a  rapid  reconnaissance  of  the  region  in  controversy,  in  the  course  of  which  a- sketch 
map  of  the  parts  traversed  was  made  and  nearly  all  the  reported  prospects  of  valuable 
minerals  were  examined.  Surface  indications  of  silver,  lead,  copper,  and  gold  ores  were 
found  to  be  widely  distributed  in  the  region,  but  there  has  been  little  development  and, 
with  one  exception,  no  commercial  ores  have  been  produced.  The  following  notes  and 
maps,  based  on  the  writer's  own  investigations  and  the  sworn  testimony  of  many  other 
witnesses,  have  been  prepared  in  view  of  the  fact  that  the  region  is  practically  unknown, 
either  geologically  or  geographically,  and  because  the  surface  indications  of  valuable  ores 
seem  to  warrant  investigation. 
GEOGRAPHY. 
Nearly  all  these  lands  (see  PI.  IV)  lie  within  the  drainage  basin  of  St.  Joe  River,  a  tribu- 
tary of  Lake  Cceur  d'Alene.  A  small  part  dong  the  southern  border  is  drained  by  Little 
North  Fork  of  the  Clearwater.  The  western  limit  of  the  area  is  near  meridian  116°  10', 
and  it  extends  eastward  to  the  Montana-Idaho  boundary,  which  in  a  sinuous  line  follows 
the  summit  of  the  Coeur  d'Alene  Range.  This  district  (see  sketch  map,  fig.  6)  lies  south 
of  and  adjacent  to  the  area  which  was  covered  by  the  Coeur  d'Alene  special  map  of  the 
United  States  Geological  Survey  and  whose  geologic  and  economic  features  have  been 
a  This  river  has  appeared  on  nearly  all  published  maps  as  the  St.  Joseph.  The  name  as  written 
above,  however,  conforms  with  local  usage  and  has  recently  been  approved  by  the  Board  on  Geo- 
graphic Names. 
b  The  act  creating  this  commission  provides  in  part  "  That  all  said  lands  shall  be  classified  as  mineral 
which  bv  reason  of  valuable  mineral  deposits  are  oDen  to  exploration,  occupation,  and  purchase  under 
the  provisions  of  the.  United  States  mining  laws,  and  the  commissioners  in  making  the  < hissiiii  'lion 
herein  provided  lor  shall  take  into  consideration  the  mineral  discovered  or  developed  on  or  adjaoeni  to 
such  lands,  and  the  geological  formation  of  all  lands  to  be  examined  and  classified,  or  the  hinds  ;id.i;< 
cent  thereto,  and  the  reasonable  probabilities  of  such  land  containing  valuable  mineral  deposits  because 
of  its  said  formation,  location,  or  character."     (Sec.  3,  act  of  February  26,  1895,  28  Stat.  L.,  683.) 
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