﻿ENDLicH.] 
  SAWATCH 
  RANGE 
  ^ANTELOPE 
  PARK. 
  159 
  

  

  of 
  the 
  trachytic 
  strata 
  form 
  its 
  confines. 
  In 
  the 
  lower 
  portion 
  of 
  the 
  

   valley 
  the 
  old 
  courses 
  of 
  the 
  Rio 
  Grande 
  can 
  readily 
  be 
  traced. 
  At 
  

   present 
  it 
  winds 
  its 
  course 
  very 
  near 
  the 
  northern 
  edge, 
  but 
  formerly 
  it 
  

   flowed 
  on 
  the 
  other 
  side. 
  Courses 
  that 
  belong 
  to 
  three 
  different 
  periods 
  

   can 
  be 
  recognized. 
  Either 
  there 
  is 
  but 
  a 
  shallow, 
  continuous 
  depression 
  

   to 
  mark 
  one 
  of 
  them, 
  or 
  a 
  series 
  of 
  swampy 
  places, 
  connected 
  with 
  each 
  

   other, 
  or 
  the 
  old 
  remnants 
  of 
  the 
  banks, 
  denoted 
  by 
  rows 
  of 
  pebbles 
  

   and 
  bowlders, 
  and 
  accumulations 
  of 
  sand. 
  We 
  have 
  here 
  an 
  excellent 
  

   illustration 
  of 
  what 
  I 
  have 
  been 
  accustomed 
  to 
  term 
  the 
  "parallel 
  shift- 
  

   ing 
  of 
  rivers." 
  The 
  general 
  course 
  of 
  the 
  Rio 
  Grande 
  in 
  Antelope 
  Park 
  

   is 
  a 
  little 
  south 
  of 
  east, 
  corresponding 
  to 
  the 
  long 
  dimension 
  of 
  the 
  

   valley 
  itself. 
  It 
  is 
  not 
  meant 
  that 
  each 
  turn 
  of 
  the 
  winding 
  river 
  is 
  

   moved 
  parallel 
  to 
  itself, 
  but 
  that 
  in 
  the 
  course 
  of 
  time 
  the 
  deposition 
  of 
  

   river-drift 
  at 
  the 
  points 
  of 
  weakest 
  current 
  will 
  produce 
  a 
  change 
  of 
  

   the 
  velocity 
  and 
  volume 
  of 
  the 
  current, 
  thereby, 
  too, 
  changing 
  the 
  places 
  

   of 
  deposition. 
  In 
  this 
  manner, 
  and 
  owing 
  to 
  these 
  changes 
  that 
  will 
  

   invariably 
  occur 
  in 
  a 
  valley 
  of 
  any 
  breadth, 
  the 
  river 
  will 
  eventually 
  

   have 
  covered 
  the 
  entire 
  width 
  of 
  the 
  depression, 
  so 
  far 
  as 
  steep 
  slopes 
  

   on 
  either 
  side 
  may 
  permit 
  it 
  to 
  travel 
  parallel 
  to 
  its 
  own 
  general 
  course. 
  

   This 
  accounts 
  for 
  the 
  fact 
  that 
  often 
  valleys 
  of 
  considerable 
  breadth, 
  

   but 
  having 
  a 
  level 
  surface, 
  are 
  found 
  to 
  be 
  covered 
  entirely 
  with 
  river- 
  

   drift. 
  In 
  a 
  case 
  of 
  that 
  kind 
  it 
  is 
  tempting 
  to 
  assume 
  an 
  enormous 
  

   amount 
  of 
  water 
  as 
  having 
  passed 
  over 
  that 
  locality 
  at 
  some 
  remote 
  

   period. 
  From 
  the 
  courses 
  taken 
  by 
  the 
  Rio 
  Grande 
  in 
  former 
  times, 
  it 
  

   is 
  evident 
  that 
  the 
  river 
  covered, 
  in 
  time, 
  the 
  entire 
  valley, 
  constantly 
  

   changing, 
  as 
  it 
  did 
  ; 
  and 
  it 
  is 
  natural, 
  therefore, 
  that 
  we 
  find 
  the 
  drift, 
  

   both 
  of 
  the 
  river 
  proper 
  and 
  that 
  brought 
  to 
  it 
  by 
  its 
  tributaries, 
  distrib- 
  

   uted 
  over 
  the 
  entire 
  surface. 
  This 
  fact 
  becomes 
  all 
  the 
  more 
  striking 
  

   as 
  some 
  of 
  the 
  streams 
  entering 
  the 
  Rio 
  Grande 
  farther 
  west 
  head 
  in 
  

   the 
  metaraorphic 
  area 
  of 
  the 
  Quartzite 
  Mountains, 
  and 
  we 
  find 
  here 
  the 
  

   characteristic 
  quartzites 
  and 
  schists 
  that 
  can 
  have 
  had 
  their 
  origin 
  no- 
  

   where 
  but 
  in 
  the 
  mountains 
  cited. 
  They 
  are 
  spread 
  all 
  over 
  that 
  portion 
  

   of 
  Antelope 
  Park, 
  together 
  with 
  the 
  volcanic 
  bowlders 
  from 
  the 
  immedi- 
  

   ate 
  vicinity, 
  and 
  from 
  the 
  neighborhood 
  of 
  the 
  headwaters 
  of 
  the 
  river. 
  

   It 
  was 
  noticed 
  that 
  drift, 
  identical 
  with 
  that 
  of 
  the 
  Rio 
  Grande, 
  

   covered 
  a 
  considerable 
  portion 
  of 
  the 
  bluff 
  upon 
  which 
  stations 
  33 
  and 
  

   34 
  were 
  located, 
  about 
  900 
  feet 
  above 
  the 
  present 
  level 
  of 
  the 
  water. 
  

   It 
  seems 
  almost 
  impossible 
  to 
  account 
  for 
  the 
  presence 
  of 
  this 
  drift. 
  It 
  

   is 
  well 
  known 
  that 
  any 
  drainage 
  coming 
  from 
  the 
  north 
  could 
  not 
  have 
  

   brought 
  quartzites 
  and 
  schists 
  to 
  those 
  places, 
  as 
  none 
  occurs 
  within 
  

   reach 
  of 
  the 
  waters 
  flowing 
  from 
  that 
  direction. 
  How 
  the 
  river 
  could 
  

   have 
  reached 
  to 
  an 
  elevation 
  900 
  feet 
  higher 
  than 
  its 
  present 
  level 
  is 
  

   not 
  readily 
  understood. 
  On 
  the 
  southern 
  side 
  of 
  the 
  valley 
  the 
  trachytic 
  

   strata 
  were 
  observed 
  to 
  dip 
  4° 
  to 
  8° 
  toward 
  it. 
  The 
  strata 
  of 
  this 
  bluff 
  

   dip 
  toward 
  it 
  8° 
  to 
  16°. 
  Whether 
  the 
  river 
  at 
  one 
  time 
  flowed 
  at 
  a 
  

   much 
  higher 
  elevation 
  than 
  at 
  present, 
  depositing 
  its 
  drift 
  where 
  it 
  is 
  

   now 
  found, 
  in 
  apparently 
  so 
  abnormal 
  a 
  position, 
  and 
  whether 
  through 
  

   a 
  subsidence 
  indicated 
  by 
  the 
  synclinal 
  dip 
  of 
  the 
  strata 
  its 
  present 
  

   course 
  was 
  established, 
  I 
  am 
  unable 
  to 
  prove. 
  Transportation 
  by 
  

   glaciers 
  suggested 
  itself, 
  but 
  no 
  positive 
  evidence 
  of 
  moving 
  ice 
  what- 
  

   ever 
  was 
  found 
  in 
  that 
  region. 
  This 
  is 
  one 
  of 
  those 
  numerous 
  puzzling 
  

   questions 
  that 
  cannot 
  be 
  answered 
  without 
  a 
  very 
  minute 
  knowledge 
  of 
  

   both 
  the 
  geognosy 
  and 
  orography 
  of 
  the 
  entire 
  section 
  of 
  country 
  in- 
  

   volved. 
  I 
  merely 
  make 
  mention 
  hereof 
  the 
  fact, 
  as 
  I 
  have 
  several 
  more 
  

   localities 
  farther 
  south 
  to 
  discuss, 
  where 
  analogous 
  occurrences 
  were 
  

   observed. 
  Between 
  Crooked 
  Creek 
  and 
  the 
  Rio 
  Grande, 
  above 
  Ante- 
  

  

  