﻿198 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  About 
  12 
  miles 
  above 
  Trinidad 
  coal 
  crops 
  out 
  on 
  a 
  level 
  with 
  the 
  river- 
  

   bed. 
  Several 
  small 
  openings 
  were 
  seen 
  there, 
  but 
  were 
  not 
  examined, 
  

   as 
  evidently 
  no 
  work 
  was 
  being 
  done. 
  At 
  that 
  locality 
  the 
  bed 
  was 
  

   thicker 
  than 
  at 
  either 
  of 
  the 
  two 
  preceding 
  ones. 
  

  

  CORRELATION 
  OF 
  COAL-BEDS. 
  

  

  As 
  has 
  been 
  stated 
  above, 
  we 
  have 
  in 
  the 
  coal-bearing 
  group 
  of 
  the 
  

   Trinidad 
  region 
  two 
  horizons 
  of 
  coal-deposits 
  — 
  the 
  lower 
  and 
  the 
  upper. 
  

   As 
  belonging 
  to 
  the 
  former 
  I 
  count 
  the 
  main 
  banks 
  south 
  of 
  Trinidad, 
  the 
  

   outcrops 
  on 
  the 
  Purgatorio 
  and 
  the 
  Cucharas 
  mines, 
  to 
  the 
  latter 
  the 
  

   occurrences 
  at 
  stations 
  125, 
  138, 
  and 
  at 
  a 
  number 
  of 
  other 
  unimportant 
  

   points. 
  It 
  has 
  been 
  mentioned 
  that 
  the 
  entire 
  group 
  forms 
  a 
  " 
  trough" 
  or 
  

   " 
  basin 
  ". 
  At 
  its 
  western 
  edge 
  the 
  dip 
  of 
  the 
  strata 
  is 
  eastward 
  ; 
  from 
  its 
  

   northern 
  border 
  they 
  dip 
  south, 
  and 
  the 
  eastern 
  bluffs 
  show 
  an 
  inclination 
  

   westward. 
  At 
  Trinidad, 
  on 
  the 
  north 
  side 
  of 
  the 
  river, 
  a 
  northerly 
  dip, 
  

   combined 
  with 
  the 
  western 
  one, 
  can 
  be 
  observed. 
  This 
  continues 
  for 
  

   some 
  distance, 
  until 
  it 
  is 
  changed 
  south 
  of 
  the 
  Cucharas, 
  where 
  a 
  dip 
  to 
  

   the 
  southward 
  sets 
  in. 
  South 
  of 
  Trinidad 
  (5,980 
  feet, 
  elevation 
  of 
  camp,) 
  

   the 
  base 
  of 
  the 
  main 
  bank 
  is 
  about 
  590 
  feet 
  above 
  tbe 
  town, 
  giving 
  it 
  an 
  

   absolute 
  elevation 
  of 
  6,570 
  feet. 
  On 
  the 
  Cucharas 
  the 
  altitude 
  above 
  sea- 
  

   level 
  of 
  the 
  mines 
  is 
  about 
  6,390 
  feet. 
  Allowing 
  for 
  the 
  synclinal 
  north 
  to 
  

   south 
  fold, 
  the 
  existence 
  of 
  which 
  has 
  been 
  mentioned 
  above, 
  and 
  con- 
  

   sidering 
  that 
  the 
  southerly 
  dip 
  commences 
  but 
  a 
  short 
  distance 
  below 
  

   the 
  Cucharas, 
  which 
  dip 
  will 
  elevate 
  the 
  coal-beds, 
  we 
  find 
  the 
  Cucharas 
  

   coal-beds 
  180 
  feet 
  lower 
  than 
  those 
  of 
  Trinidad, 
  just 
  about 
  at 
  the 
  locality 
  

   where 
  we 
  would 
  expect 
  to 
  find 
  them. 
  In 
  the 
  coal-bearing 
  beds 
  south 
  

   of 
  Trinidad 
  a 
  dip 
  to 
  the 
  northwest 
  is 
  noticeable. 
  It 
  is 
  very 
  slight, 
  

   amounting 
  to 
  about 
  1° 
  or 
  a 
  little 
  more. 
  At 
  that 
  point 
  the 
  coal 
  is 
  590 
  

   feet 
  above 
  the 
  river. 
  Allowing 
  for 
  this 
  dip 
  with 
  slight 
  variation, 
  and 
  

   the 
  increased 
  height 
  of 
  the 
  river-bed 
  as 
  we 
  travel 
  up-stream, 
  we 
  would 
  

   again 
  find 
  the 
  coal 
  on 
  a 
  level 
  with 
  the 
  river 
  where 
  it 
  was 
  actually 
  observed. 
  

   In 
  addition 
  to 
  this 
  stratigraphical 
  evidence 
  we 
  have 
  the 
  similarity 
  of 
  

   the 
  beds 
  accompanying 
  the 
  coal 
  to 
  support 
  the 
  view 
  that 
  these 
  three 
  

   localities 
  show 
  outcrops 
  belonging 
  to 
  the 
  same 
  horizon. 
  Farther 
  up 
  

   the 
  river, 
  the 
  coal, 
  if 
  it 
  still 
  continues, 
  dips 
  under, 
  is 
  hidden 
  from 
  sight, 
  

   and 
  does 
  not 
  appear 
  on 
  the 
  face 
  of 
  the 
  western 
  bluffs. 
  This 
  again 
  

   argues 
  for 
  the 
  acceptation 
  of 
  an 
  unconformability 
  between 
  the 
  Creta- 
  

   ceous 
  and 
  the 
  coal-bearing 
  series. 
  The 
  outcrops 
  found 
  near 
  stations 
  125 
  

   and 
  138, 
  I 
  regard 
  as 
  belonging 
  to 
  the 
  upper 
  horizon, 
  a 
  conclusion 
  that 
  

   is 
  sustained 
  by 
  the 
  character 
  of 
  the 
  accompanying 
  strata. 
  From 
  Fish- 
  

   er's 
  Peak, 
  a 
  section 
  (Section 
  XXI) 
  was 
  taken 
  following 
  approximately 
  

   the 
  course 
  of 
  the 
  Purgatorio 
  and 
  its 
  southern 
  fork. 
  This 
  will 
  explain 
  

   more 
  readily 
  than 
  otherwise 
  could 
  be 
  done 
  the 
  relative 
  positions 
  occu- 
  

   l)ied 
  by 
  the 
  various 
  formations 
  and 
  their 
  members. 
  Leaning 
  at 
  a 
  high 
  

   angle 
  against 
  the 
  metamorphic 
  rocks 
  of 
  the 
  Sangre 
  de 
  Cristo, 
  are 
  the 
  

   red 
  Carboniferous 
  sandstones 
  (a) 
  ; 
  with 
  a 
  vertical 
  dip, 
  the 
  sandstones 
  of 
  

   the 
  Dakota 
  group 
  {h) 
  follow, 
  and 
  after 
  them 
  the 
  dark 
  grey 
  Colorado 
  

   shales 
  (c). 
  These 
  latter 
  afford 
  but 
  very 
  poor 
  opportunity 
  of 
  studying 
  

   their 
  dip, 
  more 
  particularly 
  after 
  we 
  have 
  [)assed 
  the 
  slight 
  rise 
  pro- 
  

   duced 
  by 
  this 
  interstratum 
  of 
  sandstones 
  \d). 
  The 
  shales 
  appear 
  as 
  

   covered 
  by 
  the 
  yellow 
  shales 
  and 
  sandstones 
  (e) 
  of 
  tbe 
  prominent 
  bluff 
  

   upon 
  which 
  station 
  125 
  was 
  located. 
  At 
  the 
  junction 
  between 
  the 
  two, 
  

   the 
  dip 
  of 
  the 
  Colorado 
  shales 
  has 
  not 
  been 
  given 
  because 
  it 
  was 
  too 
  

   much 
  obscured 
  to 
  admit 
  of 
  any 
  definite 
  determination. 
  At 
  an 
  angle 
  of 
  

   4° 
  to 
  6° 
  the 
  sandstones 
  and 
  shales 
  dip 
  eastward, 
  soon 
  causing 
  the 
  dis- 
  

  

  