﻿36 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY, 
  

  

  topographical 
  and 
  geological, 
  and 
  in 
  the 
  succeeding 
  chapters 
  will 
  take 
  

   them 
  up 
  more 
  in 
  detail, 
  and 
  then 
  consider 
  separately 
  the 
  various 
  forma- 
  

   tions 
  represented 
  in 
  the 
  district. 
  

  

  The 
  region, 
  we 
  might 
  say, 
  was 
  entirely 
  unexplored. 
  Gunnison, 
  in 
  1853, 
  

   passed 
  just 
  north 
  of 
  it, 
  and 
  although 
  he 
  puts 
  a 
  portion 
  on 
  his 
  map, 
  it 
  was 
  

   outside 
  of 
  his 
  line 
  of 
  march, 
  and 
  it 
  is 
  therefore 
  necessarily 
  incorrect. 
  

   Along 
  his 
  line 
  of 
  travel 
  his 
  map 
  is 
  very 
  correct. 
  Captain 
  Macomb 
  in 
  

   1859 
  traveled 
  across 
  the 
  extreme 
  southwestern 
  corner 
  of 
  the 
  district 
  

   just 
  beyond 
  the 
  point 
  we 
  reached 
  in 
  our 
  work. 
  

  

  The 
  district, 
  as 
  laid 
  out 
  before 
  we 
  took 
  the 
  field, 
  extended 
  15 
  miles 
  into 
  

   Utah. 
  From 
  the 
  Sierra 
  la 
  Sal 
  we 
  worked 
  23 
  miles 
  to 
  the 
  westward, 
  

   that 
  is, 
  about 
  36 
  miles 
  over 
  the 
  boundary-line 
  between 
  Colorado 
  and 
  

   Utah. 
  About 
  1,200 
  square 
  miles 
  of 
  our 
  work 
  were 
  in 
  Utah. 
  

  

  