﻿H. 
  W. 
  Turner 
  — 
  Gold 
  Ores 
  of 
  California. 
  375 
  

  

  character. 
  The 
  vein 
  is 
  known 
  as 
  the 
  Pinkstown 
  ledge. 
  It 
  is 
  

   located 
  about 
  a 
  half 
  mile 
  due 
  south 
  of 
  the 
  highest 
  point 
  of 
  Big 
  

   Bend 
  Mountain 
  (Bidwell 
  Bar 
  atlas 
  sheet). 
  The 
  ledge 
  strikes 
  

   F. 
  13° 
  W. 
  and 
  dips 
  at 
  a 
  high 
  angle 
  (about 
  80°). 
  It 
  is 
  from 
  

   two 
  to 
  three 
  feet 
  wide 
  where 
  best 
  exposed 
  at 
  the 
  north 
  end, 
  

   and 
  is 
  composed 
  of 
  a 
  soft 
  heavy 
  mineral, 
  some 
  of 
  which 
  is 
  

   coarsely 
  crystalline, 
  with 
  a 
  granular 
  structure, 
  but 
  most 
  of 
  it 
  

   is 
  finer 
  grained 
  with 
  a 
  schistose 
  arrangement 
  of 
  the 
  granules. 
  

   JSTo 
  single 
  crystals 
  of 
  the 
  mineral 
  were 
  noted 
  having 
  a 
  greater 
  

   maximum 
  diameter 
  than 
  five-eighths 
  of 
  an 
  inch. 
  Some 
  of 
  

   them 
  show 
  plainly 
  a 
  characteristic 
  cleavage. 
  Dr. 
  Hillebrand 
  

   made 
  a 
  chemical 
  examination 
  of 
  this 
  soft 
  mineral 
  and 
  reported 
  

   it 
  to 
  be 
  barite. 
  Three 
  sections 
  of 
  the 
  barite 
  were 
  examined 
  

   microscopically, 
  and 
  these 
  show 
  that 
  when 
  fresh 
  there 
  is 
  

   scarcely 
  any 
  impurity 
  in 
  the 
  mineral, 
  and 
  in 
  fact 
  no 
  other 
  sub- 
  

   stance 
  was 
  noted 
  except 
  scattered 
  minute 
  reddish 
  opaque 
  grains 
  

   which 
  as 
  seen 
  under 
  the 
  microscope 
  are 
  reddish-yellow 
  by 
  

   reflected 
  light, 
  without 
  metallic 
  luster. 
  They 
  may 
  be 
  limonite. 
  

   Many 
  of 
  the 
  barite 
  grains 
  show 
  distinct 
  cleavages 
  which 
  appear 
  

   in 
  the 
  thin 
  sections 
  to 
  intersect 
  at 
  nearly 
  right 
  angles. 
  A 
  

   tendency 
  to 
  a 
  radial 
  structure 
  like 
  that 
  of 
  epidote 
  was 
  noted 
  at 
  

   several 
  points. 
  The 
  relief 
  of 
  the 
  barite 
  is 
  rather 
  high. 
  A 
  

   sample 
  was 
  examined 
  for 
  gold 
  by 
  Dr. 
  Stokes, 
  who 
  reported 
  

   that 
  " 
  the 
  barite 
  contains 
  gold 
  but 
  too 
  small 
  in 
  amount 
  to 
  be 
  

   determined 
  in 
  the 
  wet 
  way." 
  There 
  is 
  said, 
  however, 
  to 
  be 
  

   enough 
  gold 
  in 
  the 
  deposit 
  to 
  pay 
  to 
  work, 
  and 
  the 
  writer 
  

   understood 
  that 
  the 
  owner 
  of 
  the 
  ledge 
  obtained 
  gold 
  from 
  it 
  

   by 
  grinding 
  up 
  the 
  ore 
  in 
  a 
  hand 
  mortar, 
  and 
  panning 
  it. 
  

  

  A 
  considerable 
  part 
  of 
  Big 
  Bend 
  Mountain, 
  as 
  exposed 
  along 
  

   the 
  road 
  from 
  the 
  bridge 
  over 
  the 
  west 
  branch 
  of 
  the 
  north 
  

   fork 
  of 
  the 
  Feather 
  river 
  to 
  the 
  abandoned 
  village 
  of 
  Big 
  

   Bend, 
  is 
  made 
  up 
  of 
  clay 
  slates 
  probably 
  Paleozoic 
  in 
  age, 
  with 
  

   layers 
  of 
  greenstone 
  schists, 
  representing 
  original 
  augitic 
  tuffs. 
  

   The 
  rocks 
  along 
  the 
  east 
  and 
  south 
  base 
  of 
  the 
  mountain 
  as 
  

   seen 
  along 
  the 
  river 
  (the 
  north 
  fork 
  of 
  the 
  Feather) 
  are 
  almost 
  

   entirely 
  greenstones, 
  with 
  one 
  or 
  two 
  layers 
  of 
  sedimentary 
  

   mica-schists. 
  These 
  greenstones 
  are 
  largely 
  amphibolitic 
  rocks 
  

   representing 
  original 
  surface 
  lavas 
  and 
  tuffs, 
  probably 
  augitic 
  

   porphyrites, 
  but 
  now 
  containing 
  little 
  or 
  no 
  augite. 
  The 
  

   exact 
  nature 
  of 
  the 
  schist 
  enclosing 
  the 
  barite 
  vein 
  was 
  not 
  

   determined. 
  The 
  south 
  extension 
  of 
  the 
  Pinkstown 
  ledge 
  

   owned 
  by 
  Clarke 
  was 
  examined 
  but 
  no 
  barite 
  was 
  found, 
  the 
  

   rock 
  on 
  the 
  dump 
  being 
  a 
  white, 
  fine 
  grained 
  schist, 
  with 
  a 
  

   greasy 
  feel. 
  This 
  as 
  seen 
  in 
  this 
  section 
  is 
  composed 
  chiefly 
  

   of 
  minute, 
  brightly 
  polarizing 
  fibers, 
  perhaps 
  talc, 
  with 
  numer- 
  

   ous 
  minute 
  cubes 
  of 
  pyrite, 
  arranged 
  in 
  rows. 
  

  

  