﻿124 
  H. 
  T. 
  Hill 
  — 
  Ouachita 
  Mountain 
  System, 
  etc. 
  

  

  Resume 
  of 
  History 
  recorded 
  in 
  the 
  Ouachita 
  System. 
  

  

  1. 
  There 
  are 
  evidences 
  of 
  a 
  Post-Silurian 
  movement 
  in 
  the 
  

   Buckhorn 
  and 
  Red 
  Bird 
  unconformities. 
  

  

  2. 
  The 
  great 
  folding 
  and 
  elevation 
  of 
  the 
  system 
  were 
  after 
  

   the 
  close 
  of 
  the 
  Carboniferous 
  period, 
  probably 
  during 
  the 
  Per- 
  

   mian, 
  as 
  shown 
  by 
  the 
  participation 
  of 
  the 
  rocks 
  of 
  the 
  former 
  

   period 
  in 
  the 
  movement, 
  and 
  Pre-Triassic, 
  if 
  the 
  upper 
  Red 
  Beds 
  

   are 
  of 
  that 
  age. 
  

  

  3. 
  A 
  second 
  or 
  lateral 
  movement 
  must 
  have 
  taken 
  place 
  after 
  

   1 
  this 
  folding 
  by 
  which 
  the 
  folds 
  were 
  bent 
  into 
  S-shaped 
  flexures. 
  

  

  This 
  movement 
  preceded 
  the 
  Red 
  Bed 
  epoch. 
  

  

  4. 
  The 
  marked 
  but 
  not 
  excessive 
  disturbance 
  of 
  the 
  Red 
  Beds 
  

   indicates 
  movement 
  and 
  displacement 
  after 
  their 
  deposition 
  and 
  

   previous 
  to 
  the 
  Trinity 
  epoch. 
  

  

  5. 
  The 
  Lower 
  Cretaceous 
  Comanche 
  series 
  — 
  which 
  may 
  be 
  

   partly 
  Jurassic 
  — 
  was 
  deposited 
  against 
  and 
  not 
  over 
  these 
  moun- 
  

   tains, 
  and 
  show 
  in 
  themselves 
  no 
  folding 
  or 
  other 
  disturbance 
  

   except 
  such 
  faulting 
  as 
  may 
  be 
  attributed 
  to 
  the 
  Post 
  Upper 
  

   Cretaceous 
  continental 
  movement. 
  

  

  6. 
  The 
  Upper 
  Cretaceous, 
  the 
  Marine 
  Eocene 
  and 
  the 
  Quater- 
  

   nary 
  along 
  the 
  southeastern 
  and 
  eastern 
  border 
  of 
  the 
  system 
  in 
  

   Arkansas 
  were 
  also 
  deposited 
  against 
  and 
  not 
  entirely 
  over 
  the 
  

   system, 
  and, 
  like 
  the 
  Comanche 
  series, 
  reveal 
  no 
  participation 
  in 
  

   adjacent 
  mountain 
  folding, 
  but 
  merely 
  alternations 
  of 
  subsidence 
  

   and 
  elevation. 
  

  

  V. 
  This 
  system 
  has 
  undergone 
  extensive 
  erosions 
  throughout 
  

   Post-Carboniferous 
  time, 
  and 
  its 
  sediments 
  have 
  contributed 
  to 
  

   all 
  later 
  deposits. 
  

  

  8. 
  The 
  western 
  portion 
  of 
  the 
  mountain 
  system 
  was 
  in 
  parts 
  

   submerged 
  during 
  the 
  Red 
  Bed 
  epoch 
  [Triassic?] 
  and 
  completely 
  

   degraded 
  or 
  buried 
  beneath 
  the 
  sediments 
  of 
  the 
  great 
  Tertiary 
  

   lake 
  which 
  constitutes 
  the 
  formation 
  of 
  the 
  Llano 
  Estacado. 
  

  

  9. 
  The 
  relation 
  of 
  this 
  system 
  to 
  the 
  Rocky 
  Mountain 
  move- 
  

   ment 
  is 
  to 
  be 
  determined. 
  

  

  The 
  mountains 
  of 
  the 
  Ouachita 
  system, 
  including 
  the 
  eastern 
  

   or 
  Arkansas- 
  Choctaw 
  division, 
  the 
  central 
  or 
  Wapenucka 
  Lime- 
  

   stone 
  district, 
  the 
  Arbuckle 
  division 
  and 
  the 
  Wichitas, 
  should 
  

   no 
  longer 
  be 
  omitted 
  from 
  our 
  maps, 
  for 
  together 
  they 
  consti- 
  

   tute 
  the 
  foundation 
  of 
  all 
  later 
  geologic 
  structure 
  in 
  the 
  Texas 
  

   region, 
  differentiating 
  it 
  from 
  the 
  Kansas-Missouri 
  region 
  in 
  

   both 
  present 
  and 
  past 
  geologic 
  times 
  back 
  to 
  the 
  earlier 
  Meso- 
  

   zoic 
  epochs, 
  and 
  influencing 
  all 
  the 
  main 
  river 
  courses 
  of 
  Indian 
  

   Territory 
  whose 
  great 
  southward 
  bends 
  are 
  an 
  adaptation 
  to 
  

   the 
  strike 
  of 
  this 
  mountain 
  system, 
  the 
  Washita 
  alone 
  having 
  

   cut 
  through 
  it. 
  

  

  The 
  mountains 
  are 
  also 
  interesting 
  from 
  their 
  exceedingly 
  

   diverse 
  structure 
  and 
  composition, 
  and 
  from 
  the 
  fact 
  that, 
  with 
  

   the 
  exception 
  of 
  the 
  Uintas, 
  they 
  are 
  the 
  only 
  east 
  and 
  west 
  

   system 
  on 
  our 
  continent. 
  

  

  