﻿98 
  KEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  both 
  SO 
  great 
  that 
  tbe 
  results 
  of 
  more 
  modern 
  erosion 
  have 
  concealed 
  

   the 
  evidences 
  of 
  glacial 
  action. 
  A 
  detailed 
  study 
  would 
  doubtless 
  reveal 
  

   abundant 
  evidence 
  of 
  the 
  former 
  existence 
  of 
  glaciers. 
  

  

  The 
  Sierra 
  la 
  Sal 
  presents 
  one 
  of 
  the 
  most 
  promising 
  fields 
  for 
  future 
  

   detailed 
  investigation 
  to 
  be 
  found 
  in 
  any 
  part 
  of 
  the 
  West, 
  and 
  will 
  

   well 
  repay 
  the 
  labors 
  of 
  the 
  geologist 
  who 
  shall 
  devote 
  himself 
  to 
  their 
  

   special 
  study. 
  

  

  BASALT. 
  

  

  The 
  basaltic 
  areas 
  of 
  the 
  district 
  are 
  very 
  few, 
  and 
  are 
  limited 
  to 
  a 
  

   few 
  capiMngs 
  south 
  of 
  the 
  Gunnison. 
  One 
  of 
  these 
  is 
  near 
  the 
  White 
  

   Earth, 
  and 
  the 
  basalt 
  rests 
  on 
  granite. 
  It 
  was 
  described 
  by 
  Dr. 
  Endlich 
  

   in 
  the 
  Eeport 
  for 
  1874, 
  (p. 
  202, 
  station 
  7.) 
  On 
  the 
  west 
  side 
  of 
  the 
  Lake 
  

   Fork, 
  at 
  station 
  2, 
  there 
  is 
  a 
  capping 
  of 
  black 
  vesicular 
  basalt, 
  and 
  again 
  

   at 
  stations 
  4 
  and 
  5. 
  In 
  all 
  these 
  localities 
  it 
  rests 
  on 
  trachyte, 
  and, 
  

   although 
  it 
  is 
  at 
  different 
  levels, 
  it 
  is 
  evidently 
  the 
  same 
  flow, 
  and 
  all 
  

   probably 
  of 
  the 
  same 
  age, 
  being 
  the 
  youngest 
  of 
  the 
  volcanics. 
  

  

  In 
  preceding 
  chapters 
  the 
  general 
  description 
  of 
  the 
  areas 
  has 
  been 
  

   given. 
  

  

  