﻿REPORT 
  OF 
  F. 
  M. 
  ENDLICH, 
  S. 
  N. 
  D., 
  GEOLOGIST 
  OF 
  THE 
  

   SOUTHEASTERN 
  DIVISION, 
  1875. 
  

  

  LETTER 
  TO 
  DR. 
  F. 
  V. 
  HAYDEN. 
  

  

  Washington, 
  D. 
  C, 
  Novemher 
  1, 
  1876. 
  

  

  Sir 
  : 
  I 
  have 
  the 
  honor 
  herewith 
  to 
  submit 
  my 
  report 
  for 
  1875, 
  as 
  geol- 
  

   ogist 
  of 
  the 
  Southeastern 
  Division 
  of 
  the 
  United 
  States 
  Geological 
  and 
  

   Geographical 
  Survey 
  of 
  the 
  Territories, 
  under 
  your 
  charge. 
  In 
  accord- 
  

   ance 
  with 
  instructions 
  received, 
  I 
  took 
  the 
  field, 
  starting 
  from 
  Denver 
  

   June 
  7, 
  1875, 
  and 
  returned 
  to 
  that 
  place 
  after 
  the 
  completion 
  of 
  the 
  

   work 
  assigned 
  to 
  me, 
  October 
  12. 
  During 
  that 
  time 
  an 
  area 
  of 
  12,500 
  

   square 
  miles 
  was 
  surveyed 
  by 
  the 
  party 
  under 
  Mr. 
  A. 
  D. 
  Wilson's 
  

   cbarge, 
  to 
  which 
  I 
  was 
  attached 
  as 
  geologist. 
  Toward 
  the 
  latter 
  part 
  

   of 
  the 
  field-season 
  fog 
  and 
  deep 
  snow 
  greatly 
  increased 
  the 
  difficulty 
  of 
  

   the 
  work, 
  and 
  impeded 
  rapid 
  progress. 
  

  

  In 
  the 
  subjoined 
  report 
  you 
  will 
  find 
  included 
  a 
  discussion 
  on 
  that 
  

   region 
  lying 
  north 
  of 
  the 
  Rio 
  Grande 
  below 
  Antelope 
  Park, 
  and 
  on 
  the 
  

   Huerfano 
  Park. 
  Both 
  these 
  sections 
  had 
  been 
  examined, 
  partially, 
  in 
  

   1874, 
  but 
  no 
  report 
  was 
  made 
  upon 
  them, 
  as 
  they 
  would 
  have 
  consti- 
  

   tuted 
  areas 
  perfectly 
  isolated 
  from 
  the 
  remaining 
  portion. 
  

  

  With 
  a 
  view 
  to 
  facilitate 
  the 
  more 
  ready 
  comprehension 
  of 
  "descrip- 
  

   tions, 
  the 
  district 
  of 
  1875 
  has 
  been 
  separated, 
  in 
  this 
  report, 
  into 
  sec- 
  

   tions 
  determined 
  by 
  toix)graphical 
  limits. 
  Five 
  such 
  sections 
  have 
  been 
  

   made, 
  and 
  to 
  each 
  of 
  them 
  one 
  chapter 
  is 
  devoted. 
  The 
  first 
  chapter 
  

   treats 
  of 
  the 
  Sangre 
  de 
  Cristo 
  Range 
  and 
  the 
  Huerfano 
  region 
  ; 
  the 
  

   second 
  of 
  San 
  Luis 
  Valley; 
  the 
  third 
  of 
  the 
  southern 
  extension 
  of 
  the 
  

   Sawatch 
  Range 
  ; 
  the 
  fourth 
  of 
  Rio 
  San 
  Juan 
  and 
  its 
  drainage 
  ; 
  and 
  

   the 
  fifth 
  of 
  the 
  Post-Cretaceous 
  formations 
  of 
  the 
  Trinidad 
  region, 
  extend- 
  

   ing 
  from 
  there 
  northward 
  to 
  the 
  Spanish 
  Peaks. 
  A 
  " 
  conclusion" 
  sum- 
  

   marizes 
  the 
  results 
  obtained 
  during 
  the 
  season, 
  and 
  discusses 
  the 
  cor- 
  

   relation 
  of 
  the 
  formations 
  then 
  examined 
  with 
  those 
  of 
  adjoining 
  dis- 
  

   tricts. 
  

  

  Added 
  to 
  the 
  report 
  is 
  an 
  appendix 
  containing 
  a 
  synopsis 
  of 
  the 
  evi- 
  

   dence 
  of 
  former 
  glaciers 
  in 
  Southern 
  Colorado 
  and 
  a 
  list 
  of 
  minerals 
  

   found 
  in 
  that 
  State, 
  as 
  complete 
  as 
  possible 
  up 
  to 
  date. 
  

  

  To 
  Mr. 
  A. 
  D. 
  Wilson, 
  topographer 
  directing, 
  and 
  to 
  Mr. 
  F. 
  Rhoda, 
  

   his 
  assistant, 
  I 
  wish 
  here 
  to 
  express 
  my 
  sincere 
  thanks 
  for 
  their 
  aid 
  

   and 
  co-operation 
  during 
  the 
  summer. 
  

  

  To 
  Mr. 
  W. 
  H. 
  Holmes 
  I 
  am 
  indebted 
  for 
  the 
  preparation 
  of 
  illustrations, 
  

   sections, 
  and 
  maps. 
  

  

  Hoping 
  that 
  this 
  report 
  may 
  meet 
  your 
  requirements, 
  I 
  have, 
  sir, 
  the 
  

   honor 
  to 
  remain, 
  your 
  obedient 
  servant. 
  

  

  FREDERIC 
  M. 
  E:NDLICH. 
  

  

  Dr. 
  F. 
  V. 
  Hayden, 
  

  

  United 
  States 
  Geologist-in-charge. 
  

  

  103 
  

  

  