﻿376 
  H. 
  W. 
  Turner- 
  — 
  Gold 
  Ores 
  of 
  California. 
  

  

  Gold 
  associated 
  with 
  talc-schists. 
  — 
  The 
  magnesian 
  rocks, 
  of 
  

   the 
  Sierra 
  ISTevada 
  consist 
  chiefly 
  of 
  serpentine 
  and 
  talc 
  and 
  

   chlorite 
  schists. 
  All 
  of 
  these 
  rocks 
  together 
  with 
  some 
  others 
  

   of 
  similar 
  origin 
  are 
  frequently 
  found 
  in 
  the 
  same 
  area, 
  the 
  

   different 
  varieties 
  alternating 
  rapidly 
  in 
  a 
  perplexing 
  manner. 
  

   There 
  are, 
  however, 
  especially 
  in 
  the 
  area 
  of 
  the 
  Bidwell 
  Bar 
  

   atlas 
  sheet 
  (Butte 
  and 
  Plumas 
  counties) 
  very 
  considerable 
  

   streaks 
  of 
  talc 
  and 
  chlorite-schists 
  with 
  little 
  or 
  no 
  serpentine. 
  

   It 
  has 
  been 
  noted 
  by 
  the 
  writer 
  that 
  while 
  quartz 
  veins 
  are 
  

   very 
  common 
  in 
  the 
  talc-schist 
  belts, 
  they 
  are 
  very 
  rare 
  in 
  the 
  

   serpentine. 
  Yeins 
  containing 
  gold 
  and 
  forming 
  pocket 
  mines 
  

   do 
  exist 
  in 
  the 
  serpentine 
  areas, 
  but 
  in 
  the 
  two 
  examples 
  which 
  

   the 
  writer 
  has 
  himself 
  seen, 
  there 
  is 
  talc-schist 
  directly 
  asso- 
  

   ciated 
  with 
  the 
  vein, 
  forming 
  one 
  or 
  both 
  walls. 
  

  

  One 
  of 
  the 
  veins 
  here 
  referred 
  to 
  occurs 
  on 
  the 
  Downieville 
  

   sheet 
  in 
  Sierra 
  County, 
  on 
  the 
  spur 
  north 
  of 
  Eock 
  Creek 
  and 
  

   one 
  and 
  a 
  half 
  miles 
  east 
  of 
  Goodyear's 
  Bar. 
  Here 
  is 
  a 
  small 
  

   quartz 
  vein 
  in 
  serpentine 
  with 
  talc-schist 
  forming 
  one 
  wall. 
  

   This 
  vein 
  had 
  evidently 
  been 
  worked 
  for 
  gold, 
  and 
  the 
  writer 
  

   was 
  informed 
  that 
  a 
  gold 
  pocket 
  was 
  found 
  in 
  it. 
  

  

  The 
  other 
  mine 
  is 
  in 
  Mariposa 
  County 
  on 
  the 
  Mariposa 
  

   Estate, 
  and 
  is 
  in 
  charge 
  of 
  Mr. 
  Ludwig, 
  who 
  kindly 
  showed 
  

   nie 
  the 
  deposit. 
  There 
  is 
  here 
  a 
  streak 
  of 
  talc-schist 
  in 
  ser- 
  

   pentine 
  near 
  the 
  west 
  border 
  of 
  the 
  large 
  belt 
  of 
  that 
  rock 
  

   that 
  extends 
  from 
  near 
  Princeton 
  to 
  Mariposa 
  forming 
  the 
  

   high 
  ridge 
  just 
  west 
  of 
  the 
  latter 
  town. 
  The 
  exact 
  locality 
  is 
  

   one 
  and 
  three-fourths 
  miles 
  a 
  little 
  south 
  of 
  east 
  from 
  Prince- 
  

   ton. 
  The 
  deposit 
  consists 
  besides 
  the 
  talc, 
  of 
  white 
  dolomite 
  

   looking 
  precisely 
  like 
  that 
  associated 
  with 
  mariposite 
  at 
  the 
  

   Josephine 
  Mine 
  near 
  Bear 
  Valley, 
  pyrite, 
  and 
  a 
  black 
  mineral, 
  

   the 
  latter 
  occurring 
  in 
  plates 
  with 
  metallic 
  surfaces 
  in 
  the 
  dolo- 
  

   mite. 
  This 
  black 
  mineral 
  was 
  determined 
  by 
  Dr. 
  W. 
  F. 
  

   Hillebrand 
  to 
  be 
  titanic 
  iron 
  ore 
  (ilmenite). 
  The 
  gold 
  occurs 
  

   native 
  in 
  the 
  talc-schist, 
  and 
  the 
  pyrite 
  and 
  ilmenite 
  are 
  also 
  

   saved 
  for 
  reduction. 
  The 
  writer's 
  notes 
  make 
  no 
  mention 
  of 
  

   quartz 
  in 
  this 
  vein. 
  

  

  As 
  stated 
  above, 
  the 
  talc, 
  chlorite, 
  and 
  other 
  associated 
  schists 
  

   form 
  considerable 
  belts 
  in 
  the 
  area 
  of 
  the 
  Bidwell 
  Bar 
  atlas 
  

   sheet, 
  and 
  contain 
  frequent 
  quartz 
  veins, 
  as 
  may 
  well 
  be 
  seen 
  

   at 
  Quartz 
  Hill 
  north 
  of 
  Lumpkin. 
  The 
  writer 
  knows 
  of 
  no 
  

   case, 
  however, 
  where 
  one 
  of 
  these 
  veins 
  has 
  proved 
  to 
  be 
  large 
  

   enough 
  and 
  to 
  contain 
  enough 
  gold 
  to 
  warrant 
  the 
  erection 
  of 
  

   a 
  quartz-mill. 
  

  

  The 
  rare 
  occurrence 
  of 
  quartz 
  veins 
  in 
  serpentine, 
  a 
  very 
  

   basic 
  magnesian 
  rock, 
  and 
  their 
  comparative 
  abundance 
  in 
  talc 
  

   rocks, 
  which 
  are 
  much 
  more 
  acid, 
  would 
  seem 
  to 
  indicate 
  a 
  con- 
  

   nection 
  between 
  quartz 
  veins 
  and 
  the 
  rock 
  in 
  which 
  they 
  form. 
  

  

  