﻿iiAiDEx] 
  LETTER 
  TO 
  THE 
  SECRETARY. 
  19 
  

  

  la 
  order 
  tliat 
  every 
  branch 
  of 
  scientific 
  study 
  and 
  investigation 
  might 
  

   have 
  proper 
  attention, 
  a 
  competeut 
  mineralogist 
  was 
  attached 
  to 
  each 
  

   division 
  of 
  the 
  Geological 
  Survey, 
  as 
  mines 
  and 
  mining 
  features 
  of 
  the 
  

   country 
  were 
  regarded 
  of 
  the 
  highest 
  scientific 
  and 
  economic 
  import- 
  

   ance. 
  • 
  

  

  During 
  the 
  prosecution 
  of 
  the 
  work 
  of 
  the 
  Survey, 
  attention 
  has 
  always 
  

   been 
  paid 
  to 
  the 
  development 
  of 
  the 
  natural 
  resources 
  of 
  the 
  country 
  

   traversed. 
  Mineral 
  and 
  agricultural 
  wealth 
  has 
  been 
  the 
  subject 
  of 
  

   especial 
  study, 
  furnishing, 
  as 
  it 
  does, 
  an 
  indication 
  of 
  the 
  future 
  pros- 
  

   pects, 
  commercially 
  and 
  financially, 
  of 
  the 
  territory 
  that 
  at 
  the 
  time 
  

   may 
  be 
  explored. 
  With 
  a 
  view 
  to 
  increase 
  the 
  scientifi^c 
  knowledge 
  

   with 
  reference 
  to 
  horizontal 
  and 
  vertical 
  distribution 
  of 
  minerals, 
  all 
  

   occurrences 
  have 
  been 
  carefully 
  noted, 
  and 
  summarized 
  in 
  published 
  

   catalogues. 
  Since 
  1873, 
  Colorado, 
  one 
  of 
  the 
  richest 
  mining 
  States 
  of 
  

   the 
  United 
  States, 
  has 
  been 
  the 
  subject 
  of 
  exploration. 
  In 
  accordance 
  

   with 
  the 
  predominating 
  industrial 
  features 
  of 
  the 
  country, 
  particular 
  

   attention 
  was 
  given 
  to 
  the 
  investigation 
  of 
  its 
  mineral 
  riches. 
  The 
  

   mines 
  of 
  all 
  the 
  principal 
  mining 
  districts 
  were 
  examined 
  by 
  experts, 
  

   and 
  reports 
  thereupon 
  were 
  published. 
  Although 
  the 
  character 
  of 
  these 
  

   reports 
  was 
  necessarily 
  such 
  that 
  no 
  direct 
  benefit 
  could 
  therefrom 
  accrue 
  

   to 
  any 
  individual 
  mine, 
  it 
  is 
  certain 
  that 
  the 
  discussion 
  of 
  such 
  districts 
  

   has 
  furnished 
  general 
  data, 
  the 
  correctness 
  and 
  impartiality 
  of 
  which 
  

   will 
  go 
  far 
  toward 
  assuring 
  mine-owners 
  and 
  workmen 
  of 
  eventual 
  suc- 
  

   cess 
  and 
  remuneration 
  in 
  the 
  work 
  they 
  have 
  undertaken. 
  It 
  has 
  been 
  

   a 
  prominent 
  feature 
  of 
  this 
  Survey 
  to 
  explore 
  (immediately 
  after 
  discov- 
  

   ery) 
  any 
  new 
  district 
  that 
  may 
  have 
  been 
  announced, 
  and 
  to 
  give, 
  as 
  

   speedily 
  as 
  possible, 
  to 
  the 
  public 
  the 
  benefit 
  of 
  such 
  explorations. 
  Thus, 
  

   the 
  first 
  authentic 
  reports 
  relative 
  to 
  the 
  famous 
  San 
  Juan 
  mines 
  are 
  to 
  

   be 
  found 
  in 
  the 
  publications 
  of 
  the 
  Survey. 
  Owing 
  to 
  the 
  organization 
  

   cf 
  the 
  parties 
  in 
  the 
  field, 
  examinations 
  of 
  such 
  nature 
  can 
  readily 
  be 
  

   made 
  without 
  the 
  loss 
  of 
  too 
  much 
  time, 
  and 
  at 
  the 
  same 
  time 
  with 
  the 
  

   cooperation 
  of 
  civil 
  engineers, 
  which 
  may 
  at 
  times 
  be 
  desired 
  by 
  the 
  

   geologist 
  or 
  mining 
  expert. 
  In 
  consequence 
  of 
  this 
  arrangement, 
  it 
  is 
  

   possible 
  for 
  each 
  party 
  to 
  obtain, 
  in 
  a 
  by 
  far 
  shorter 
  period 
  of 
  time 
  than 
  

   would 
  otherwise 
  be 
  required, 
  information 
  that 
  ranks 
  high 
  in 
  accuracy 
  

   and 
  completeness. 
  

  

  In 
  connection 
  partly 
  with 
  the 
  examination 
  of 
  mines, 
  special 
  attention 
  

   was 
  given 
  to 
  the 
  occurrence 
  of 
  minerals 
  at 
  various 
  localities 
  throughout 
  

   the 
  State. 
  The 
  result 
  derived 
  has 
  been 
  embodied 
  in 
  a 
  catalogue 
  of 
  

   Colorado 
  minerals. 
  As 
  was 
  expected, 
  it 
  has 
  been 
  gratifying, 
  and 
  the 
  

   publications 
  of 
  the 
  Survey 
  are 
  thus 
  able 
  to 
  i^resent 
  a 
  list 
  of 
  minerals 
  

   from 
  Colorado, 
  exceeding 
  in 
  number 
  200 
  species. 
  Attention 
  has 
  been 
  

   directed 
  more 
  particularly 
  — 
  for 
  obvious 
  reasons 
  — 
  to 
  those 
  that 
  there 
  

   rank 
  as 
  "ores", 
  and 
  their 
  horizontal 
  distribution 
  affords 
  important 
  in- 
  

   formation 
  as 
  to 
  the 
  character 
  and 
  location 
  of 
  the 
  mining 
  districts. 
  At 
  

   the 
  same 
  time, 
  their 
  chemical 
  constitution 
  furnishes 
  a 
  hint 
  as 
  to 
  the 
  

  

  