﻿76 
  ERPOET 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  lowing 
  year, 
  obtained 
  primordial 
  fossils. 
  In 
  New 
  Mexico, 
  Dr. 
  Newberry 
  

   found 
  the 
  Carboniferous 
  in 
  immediate 
  superposition 
  with 
  the 
  granite. 
  

  

  Was 
  the 
  land 
  in 
  our 
  district 
  in 
  Carboniferous 
  times 
  an 
  island 
  or 
  a 
  

   continental 
  projection? 
  A 
  great 
  portion 
  of 
  what 
  is 
  now 
  the 
  Sawatch 
  

   range 
  was 
  above 
  water, 
  and 
  the 
  area 
  west 
  of 
  the 
  Uncompahgre 
  may 
  

   have 
  been 
  connected 
  with 
  the 
  Sawatch 
  area, 
  but 
  in 
  what 
  manner 
  it 
  is 
  

   impossible 
  to 
  say. 
  

  

  In 
  the 
  Elk 
  Mountains 
  the 
  gypsum 
  series 
  has 
  not 
  been 
  positively 
  rec- 
  

   ognized. 
  Next 
  to 
  the 
  micaceous 
  sandstones 
  at 
  the 
  top 
  of 
  the 
  Coal- 
  

   Measures 
  is 
  a 
  conglomerate 
  composed 
  of 
  granitic 
  and 
  limestone 
  pebbles.* 
  

   Above 
  this 
  are 
  beds 
  of 
  maroon-colored 
  shales 
  and 
  sandstones, 
  followed 
  

   by 
  red 
  sandstones. 
  The 
  conglomerate 
  was 
  derived 
  from 
  the 
  degradation 
  

   of 
  land 
  that 
  was 
  composed 
  in 
  part 
  of 
  granitic 
  rocks, 
  and 
  also 
  of 
  stratified. 
  

   There 
  were 
  no 
  remains 
  to 
  tell 
  whether 
  the 
  pebbles 
  were 
  from 
  Silurian, 
  

   Devonian, 
  or 
  Carboniferous 
  strata. 
  If 
  the 
  Permian 
  rocks 
  are 
  absent, 
  it 
  

   would 
  imply 
  an 
  interval 
  between 
  the 
  Coal-Measures 
  and 
  the 
  Trias, 
  to 
  

   which 
  the 
  conglomerate 
  would 
  have 
  to 
  be 
  referred, 
  during 
  which 
  a 
  por- 
  

   tion 
  of 
  the 
  land 
  above 
  sea-level 
  must 
  have 
  been 
  composed 
  of 
  Carbon- 
  

   iferous 
  rocks. 
  If 
  so, 
  the 
  gradual 
  subsidence 
  of 
  the 
  land 
  carried 
  them 
  

   beneath 
  the 
  level 
  of 
  the 
  sea 
  as 
  the 
  deposition 
  of 
  the 
  Triassic 
  sandstones 
  

   progressed. 
  

  

  It 
  is 
  probable, 
  however, 
  that 
  the 
  conglomerate 
  marks 
  the 
  base 
  of 
  the 
  

   Permian 
  rocks, 
  and 
  that 
  the 
  maroon-colored 
  beds 
  should 
  also 
  be 
  referred 
  

   to 
  the 
  Permian. 
  If 
  so, 
  the 
  gypsum 
  which 
  characterizes 
  the 
  beds 
  else- 
  

   where 
  is 
  wanting 
  in 
  the 
  Elk 
  Mountains. 
  

  

  The 
  greenish-gray 
  micaceous 
  sandstones 
  beneath 
  the 
  conglomerate 
  in 
  

   the 
  section 
  just 
  quoted 
  seem 
  to 
  be 
  identical 
  with 
  those 
  of 
  the 
  Eagle 
  Eiver 
  

   section, 
  and 
  also 
  with 
  those 
  in 
  Four 
  Mile 
  Creek 
  Caiion 
  west 
  of 
  South 
  Park. 
  

   This 
  identity 
  is 
  not 
  only 
  lithological 
  but 
  paleontological. 
  All 
  contain 
  

   fossils 
  typical 
  of 
  the 
  Coal-Measures. 
  I 
  have 
  therefore 
  divided 
  my 
  Car- 
  

   boniferous 
  into 
  three 
  divisions, 
  as 
  follows 
  : 
  

  

  Subcarboniferous 
  — 
  Mainly 
  massive 
  limestones 
  grading 
  below 
  into 
  

   Devonian 
  1 
  

  

  Carboniferous 
  (Coal-Measures) 
  — 
  Micaceous 
  sandstones 
  with 
  limestones 
  

   near 
  the 
  base. 
  

  

  Permian 
  or 
  Permo-Carboniferous 
  — 
  Gypsiferous 
  and 
  calcareous 
  shales 
  

   and 
  sandstones, 
  limestone 
  near 
  base. 
  

  

  Mr. 
  Marvine, 
  in 
  1874, 
  recognized 
  four 
  divisions, 
  the 
  upper 
  one 
  of 
  which 
  

   was 
  red 
  sandstone 
  and 
  those 
  below 
  as 
  I 
  have 
  them. 
  Dr. 
  Endlich, 
  in 
  

   Southern 
  Colorado, 
  recognized 
  the 
  following 
  : 
  

  

  Lower 
  Carboniferous 
  — 
  limestones. 
  

  

  Upper 
  Carboniferous 
  — 
  red 
  sandstones. 
  

  

  Near 
  the 
  top 
  of 
  the 
  latter 
  in 
  some 
  localities 
  he 
  finds 
  a 
  band 
  of 
  lime- 
  

   stone. 
  I 
  give 
  the 
  following 
  table 
  for 
  comparison 
  in 
  my 
  own 
  districts 
  : 
  

  

  *See 
  section 
  of 
  inverted 
  beds, 
  Report 
  United 
  States 
  Geological 
  Survey, 
  1873, 
  p. 
  251. 
  

  

  