48  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
80°  S.  It  shows  considerable  specular  hematite,  a  little  bornite,  and  some  chaleopyrite. 
Not  enough  development  work  has  been  done  to  disclose  any  mineralization  of  commercial 
importance. 
The  Pend  Oreille  copper  properties  are  located  near  the  Northern  Pacific  Railway,  a  few 
miles  east  of  Hope.  The  country  rock  is  a  bluish-gray  shale  belonging  to  the  Wallace 
formation.  The  main  lead  is  about  11  feet  wide,  and  its  walls  are  fairly  well  defined.  It 
seems  to  trend  about  N.  55°  E.  and  to  dip  80°  E.  The  croppings  show  cupriferous  pyrite, 
but  the  vein  has  not  been  sufficiently  opened  to  reveal  its  extent  and  value. 
TROY. 
Troy  is  a  small  Montana  town  on  the  Groat  Northern  Railway.  It  is  in  the  Kootenai 
Valley,  at  the  foot  of  the  Cabinet  Mountains,  and  is  the  natural  distributing  point  for  the 
mining  properties  on  Callahan  Creek  and  Grouse  Mountain. 
CALLAHAN    CREEK.Q 
On  Callahan  Creek  are  two  lead-zinc  properties  on  fissure  veins  which  promise  to  become 
producers  of  some  importance.  There  is  also  m  prospect  farther  up  the  creek  than  these,  in 
what  was  considered  by  one  observer  to  be  a  contact  deposit.  This,  however,  was  not 
visited,  so  thai  attention  may  be  confined  to  the  two  properties  first  mentioned,  the  Big 
Eight  and  B  &  B  mines. 
The  ore  bodies  in  which  these  mines  are  located  occupy  fissures,  but  igneous  agencies 
have  been  concerned  in  their  formation,  and  they  have  a  composition  characteristic  of  j 
com  ad  deposits  rather  than  of  ordinary  fissure  veins.  The  B  &  B  and  Big  Eight  are  situ- 
ated on  the  same  fissure  or  on  two  parallel  and  only  slightly  separated  fissures  of  the  same 
system  with  a  course  of  about  X.  'A()°  W.  These  breaks  are  subsidiary  to  a  great  fault 
which  passes  between  the  mines  and  Troy  and  brings  Wallace  and  Striped  Peak  rocks  on  ] 
the  east  down  against  Creston  quartzite  and  Prichard  slate  on  the  west.  The  country  rock 
of  the  B  &  B  mine  is  typical  Pri<  hard  slate;  that  of  the  Big  Eight  is  a  grayish  quartzitib 
materia]  probably  belonging  to  the  Creston  quartzite.  Penetrating  these  sedimentariea 
and  injected  in  the  fissure  occupied  by  the  vein,  there  is  in  each  of  the  mines  a  basic  dike, 
so  far  altered  (ha;  i  s  original  petrographic  character  can  not  be  satisfactorily  determined. 
The  mineralization  seems  to  have  been  posterior  to,  but  was  possibly  in  pari  contempora- 
neous with,  the  intrusion  of  the  dike. 
In  the  Big  Eight  mine  the  vein  is  jusl  west  of  the  dike.  It  is  about  8  feet  wide,  with  walls 
fairly  well  defined  The  ore  is  rather  irregularly  distributed,  in  places  forming  most  of  the 
vein,  but  often  mixed  with  much  gangue  material  and  masses  of  country  rock.  It  is  prin- 
cipally sphalerite,  which  forms  large  masses  of  great  purity,  but  is  locally  mixed  with  a 
subordinate  quantity  of  galena.  The  gangue  is  the  most  remarkable  feature  of  the  vein, 
and  consists  chiefly  of  silicates,  including  a  pale-greenish  amphibole,  garnet,  biotite,  and  ] 
chlorite.  Calcite  and  a  little  p}7rite  occur  locally.  About  200  feet  east  of  and  parallel  to 
the  main  vein  is  a  small  vein  of  nearly  pure  galena. 
The  B  &  B  vein  has  practically  the  same  characteristics  as  the  main  vein  of  the  Big  Eight. 
The  gangue  is  likewise  chiefly  a  mixture  of  silicates,  and  the  valuable  minerals  consist  of 
sphalerite  and  galena. 
Neither  property  was  shipping  ore  when  visited,  although  both  have  shipped  considerable 
amounts  in  the  past.  The  B  &  B  was  idle,  owing,  it  was  reported,  to  litigation.  The  Big 
Eight  was  being  worked  under  a  lease  held  by  the  Batchelder  Brothers  of  Spokane,  and  had 
about  150  ton9  of  ore  on  the  dump. 
CKOl'SE    MOUNTAIN    IMtOPKRTI  KS. 
Grouse  Mountain  is  a  spur  of  the  Cabinet  Range,  lying  between  the  headwaters  of  Callahan 
and  Lake  creeks. 
a  This  region  was  visited  and  described  by  Mr.  Calkins. 
