﻿REPORT 
  OF 
  WILLIAM 
  H. 
  HOLMES. 
  GEOLOGIST 
  OF 
  THE 
  

   SAN 
  JUAN 
  DIVISION. 
  1875. 
  ' 
  

  

  LETTER 
  TO 
  DR. 
  F. 
  V. 
  HAYDEN. 
  

  

  Washington, 
  D. 
  C, 
  December 
  30, 
  1876. 
  

  

  Sir 
  : 
  Herewith 
  I 
  submit 
  my 
  report 
  ou 
  the 
  geology 
  of 
  the 
  district 
  ex- 
  

   amined 
  by 
  the 
  southwestern 
  or 
  San 
  Juan 
  division 
  during 
  the 
  season 
  of 
  

   1875. 
  

  

  Our 
  party, 
  consisting 
  of 
  George 
  B. 
  Chittenden, 
  topographer, 
  T. 
  S. 
  

   Brandegee, 
  assistant 
  topographer 
  and 
  botanist, 
  and 
  myself, 
  together 
  

   with 
  two 
  packers 
  and 
  a 
  cook, 
  took 
  the 
  field 
  at 
  Denver 
  on 
  the 
  7th 
  of 
  

   June. 
  By 
  written 
  instructions 
  from 
  you 
  we 
  were 
  directed 
  to 
  survey 
  

   the 
  area 
  which 
  is 
  "bounded 
  on 
  the 
  west 
  by 
  109° 
  30', 
  on 
  the 
  south 
  by 
  

   36° 
  45', 
  on 
  the 
  north 
  by 
  37° 
  50', 
  and 
  on 
  the 
  east 
  by 
  Mr. 
  Wilson's 
  work 
  

   of 
  1874." 
  In 
  this 
  area 
  there 
  are 
  about 
  6,500 
  square 
  miles. 
  In 
  addition 
  

   to 
  this, 
  Mr. 
  Chittenden 
  was 
  instructed 
  to 
  finish 
  out 
  the 
  edge 
  of 
  map 
  83 
  

   from 
  latitude 
  39° 
  15' 
  to 
  latitude 
  38° 
  along 
  the 
  meridian 
  104^ 
  30'. 
  This 
  

   work 
  Mr. 
  Chittenden 
  completed 
  as 
  we 
  marched 
  south, 
  without 
  inter- 
  

   fering 
  with 
  the 
  progress 
  of 
  the 
  party. 
  

  

  In 
  order 
  to 
  reach 
  our 
  district 
  in 
  the 
  southwest, 
  a 
  distance 
  of 
  some 
  350 
  

   miles 
  had 
  to 
  be 
  traversed. 
  On 
  the 
  12th 
  we 
  reached 
  Pueblo 
  ; 
  passing 
  

   south 
  from 
  this, 
  we 
  reached 
  and 
  ascended 
  the 
  Huerfano 
  Eiver 
  and 
  

   entered 
  San 
  Luis 
  Park 
  by 
  way 
  of 
  Mosca 
  Pass. 
  On 
  the 
  19th 
  we 
  arrived 
  

   at 
  Del 
  Norte. 
  A 
  portion 
  of 
  our 
  supplies 
  had 
  been 
  forwarded 
  to 
  this 
  

   point 
  by 
  freight, 
  but 
  as 
  nothing 
  had 
  arrived 
  and 
  no 
  word 
  came 
  of 
  their 
  

   approach, 
  I 
  elfected 
  an 
  exchange 
  with 
  a 
  merchant 
  of 
  the 
  place 
  by 
  which 
  

   we 
  were 
  enabled 
  to,push 
  forward 
  without 
  delay. 
  

  

  From 
  Del 
  Norte 
  we 
  passed 
  up 
  the 
  Rio 
  Grande 
  for 
  some 
  60 
  miles. 
  Leav- 
  

   ing 
  the 
  river 
  10 
  miles 
  above 
  Antelope 
  Park 
  we 
  crossed 
  the 
  ocean 
  divide 
  

   by 
  way 
  of 
  Weminuche 
  Pass 
  and 
  camped 
  in 
  the 
  upper 
  valley 
  of 
  the 
  Eio 
  

   Piedra, 
  a 
  tributary 
  of 
  the 
  Rio 
  San 
  Juan. 
  Finding 
  no 
  trail 
  near 
  the 
  

   base 
  of 
  the 
  mountains 
  and 
  not 
  wishing 
  to 
  descend 
  so 
  far 
  as 
  the 
  cross- 
  

   ing 
  of 
  the 
  old 
  Spanish 
  trail, 
  we 
  decided 
  to 
  move 
  directly 
  westward, 
  

   so 
  as 
  to 
  cross 
  the 
  headwaters 
  of 
  the 
  Pinos 
  and 
  Florida 
  Rivers. 
  At 
  first 
  

   very 
  rough 
  traveling 
  was 
  encountered, 
  but 
  by 
  the 
  middle 
  of 
  the 
  second 
  

   day 
  we 
  reached 
  a 
  lovely 
  parked 
  country 
  and 
  soon 
  found 
  a 
  trail 
  which 
  

   led 
  out 
  to 
  the 
  Spanish 
  trail 
  at 
  the 
  point 
  where 
  it 
  crosses 
  the 
  Florida. 
  

   By 
  the 
  latter 
  trail 
  we 
  reached 
  the 
  Rio 
  Animas, 
  and, 
  ou 
  the 
  29th 
  of 
  June, 
  

   the 
  eastern 
  border 
  of 
  our 
  district. 
  During 
  this 
  three 
  weeks 
  of 
  travel 
  we 
  

   had 
  been 
  passing 
  through 
  the 
  districts 
  surveyed 
  by 
  Mr. 
  Wilson 
  and 
  

   Dr. 
  Endlich 
  in 
  the 
  years 
  1873 
  and 
  1874; 
  and 
  having 
  with 
  us 
  their 
  map, 
  

   which 
  reached 
  to 
  meridian 
  108°, 
  we 
  had 
  no 
  great 
  difficulty 
  in 
  beginning 
  

   work. 
  The 
  wagon-trail 
  which 
  now 
  leads 
  from 
  the 
  Animas 
  Valley 
  to 
  the 
  

   La 
  Plata 
  mining 
  camp, 
  crosses 
  our 
  eastern 
  line 
  in 
  latitude 
  37° 
  15', 
  and 
  our 
  

   first 
  station 
  was 
  made 
  near 
  this, 
  on 
  the 
  divide 
  between 
  the 
  Rio 
  La 
  Plata 
  

   and 
  the 
  Animas, 
  midway 
  between 
  the 
  northern 
  and 
  southern 
  bounda- 
  

  

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