IRON   ORES  OF   THE  WESTERN   UNITED  STATES  AND 
BRITISH  COLUMBIA. 
By  C.  K.  Leith. 
INTRODUCTION. 
An  insignificant  part  of  the  iron-ore  production  of  the  United  States  has  come  from  west 
of  Mississippi  River-  in  recent  years  about  2  per  cent.  Nevertheless,  in  that  vast  region 
there  are  many  ore  deposits  known  and  doubtless  more  to  be  discovered.  Present  eco- 
nomic condit  ions  demand  t  hat  t  he  nat  nre.  extent ,  and  availability  of  l  lie  ores  of  this  region 
should  he  generally  known.  The  present  writer  has  given  attention  primarily  to  t  he  geo- 
logical relations  and  origin  of  the  ores  as  affording  a  basis  of  comparison  with  present  pro- 
ducing districts  of  the  United  States  rather  than  to  estimates  of  tonnage  and  study  of 
present  commercial  conditions,  although  some  incidental  attention  has  necessarily  been^ 
paid  to  these  matters.  In  the  fall  of  l!!().'i  the  iron  ores  of  Iron  County,  southern  Utah] 
were  examined  and  a  brief  report  published  in  the  Economic  Bulletin  for  thai  year.4 
The  work  of  the  past   two  held  seasons,  including  detailed  mapping  of  the  Utah  deposits,  is 
summarized  below. 
GENERAL  RECONNAISSANCE. 
BARTVILLE,  WYOMING. 
In  1904  the  deposits  at  Sunrise,  in  the  Hartville  district  of  Wyoming,  were  looked  over. 
The  facts  observed  correspond  with  the  description  by  W.  S.  Tangier  Smith  in  the  folio  on 
this  district.''  The  ores  occur  in  the  Whalen  group  of  limestone,  quartzite,  and  quartzosl 
schist,  extending  along  the  west  side  of  Whalen  Canyon,  south  and  west  of  Fredericks,  to 
Sunrise  and  Hartville.  Ore  is  mined  at  present  only  at  Sunrise.  Here  an  open  pit,  with 
terraces  rising  toward  the  north,  exposes  the  ore  and  its  associated  rocks.  The  foot  wall 
on  t  he  west  consists  of  handed  calcareous  and  siliceous  schists  and  cherts.  Smit  h  describe! 
these  as  schistose  quartzites.  The  writer's  examination,  both  in  the  held  and  with  the 
microscope,  disclosed  no  positive  evidence  of  their  sedimentary  origin,  though  he  has  no 
reason  to  doubt  that  Smith's  conclusion  is  correct.  These  grade  up  into  the  ore  through 
phases  which  in  the  Lake  Superior  country  would  be  called  ferruginous  cherts.  The  hang- 
ing wall  is  of  much  the  same  nature.  The  structure  of  both  the  foot  and  hanging  walls, 
whether  it  be  bedding  or  schistosity,  dips  steeply  to  the  east.  Immediately  to  the  east  of 
the  deposit,  near  the  power  house,  and  also  to  the  sout  Invest ,  are  limestones  of  the  Whalen 
series.  Resting  unconformably  upon  the  ores  and  associated  rocks  are  Carboniferous  lime- 
stones and  sandstones,  forming  an  amphitheater,  opening  to  the  southwest,  about  the  ores 
and  associated  Whalen  rocks.  The  lateral  extent  of  the  ore  to  the  northwest  is  hidden  by 
the  capping  of  Carboniferous  sandstones  and  limestones.  Drilling  is  said  to  have  shown  the 
extension  of  the  ore  beneath  these  rocks  to  a  considerable  distance.  Here  it  will  have  to 
be  won  by  underground  methods. 
a  Bull.  U.S.  Geol.  Survey    No.  225,  1903,  pp.  'J-'.'  237. 
^Geologic  At  hi..  U.  S.,  folio  91,  U.  S.  Geol.  Survey,  1903. 
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