﻿404 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  patches, 
  and 
  the 
  terraced 
  slopes 
  are 
  covered 
  with 
  grass, 
  and 
  in 
  the 
  

   upper 
  and 
  middle 
  portion 
  of 
  the 
  range 
  intermixed 
  with 
  quaking 
  asps. 
  

  

  If 
  we 
  admit 
  in 
  the 
  Blue 
  Eiver 
  Valley 
  the 
  existence 
  of 
  an 
  upper 
  as 
  

   well 
  as 
  a 
  middle 
  valley, 
  the 
  lower 
  valley 
  would 
  theu 
  have 
  its 
  beginning 
  

   at 
  the 
  Valley 
  Butte, 
  and 
  extend 
  to 
  the 
  Grand 
  Eiver 
  Junction, 
  giviug 
  it 
  

   an 
  extent 
  of 
  12 
  miles. 
  

  

  The 
  valley 
  features 
  are 
  here 
  particularly 
  uniform 
  in 
  their 
  character- 
  

   istics, 
  and 
  correspond 
  to 
  the 
  regular, 
  gradually 
  rising 
  terraced 
  slopes 
  

   of 
  its 
  margins. 
  The 
  river-channel 
  in 
  the 
  lower 
  valley 
  is 
  cut 
  deeper 
  

   than 
  in 
  the 
  Middle 
  Blue 
  Valley, 
  and 
  the 
  first 
  terraces 
  that 
  stretch 
  

   along, 
  and 
  sometimes 
  very 
  close 
  to 
  the 
  river, 
  are 
  from 
  50 
  to 
  SO 
  feet 
  

   high. 
  

  

  The 
  whole 
  length 
  of 
  the 
  Blue 
  Eiver 
  from 
  its 
  mouth 
  to 
  its 
  sources 
  in 
  

   the 
  amphitheater 
  below 
  Quandary 
  Peak 
  is 
  59 
  miles. 
  Tbe 
  average 
  fall 
  

   of 
  the 
  river 
  is 
  57^^^ 
  feet 
  per 
  mile, 
  and 
  the 
  head 
  of 
  the 
  valley 
  lies 
  3,4U0 
  

   feet 
  above 
  its 
  junction 
  with 
  the 
  Grand. 
  

  

  EAGLE 
  EIVER. 
  

  

  As 
  Eagle 
  Eiver 
  belongs 
  only 
  in 
  part 
  to 
  the 
  district 
  of 
  my 
  special 
  

   observation, 
  the 
  description 
  will 
  be 
  only 
  fragmentary, 
  and 
  irom 
  the 
  fact 
  

   t 
  at 
  the 
  whole 
  length 
  of 
  this 
  river 
  is 
  60 
  miles 
  from 
  its 
  source 
  to 
  its 
  

   iunction 
  with 
  the 
  Grand 
  Eiver, 
  only 
  22 
  miles, 
  or 
  about 
  one-third 
  of 
  its 
  

   length, 
  will 
  be 
  contained 
  in 
  this 
  description. 
  

  

  Where 
  the 
  main 
  range, 
  past 
  its 
  intersection 
  with 
  the 
  Park 
  Eange,* 
  

   trends 
  westward 
  to 
  connect 
  with 
  the 
  Sawatch 
  Eange, 
  we 
  find 
  6 
  miles 
  

   west 
  of 
  the 
  Park 
  Eange, 
  and 
  almost 
  in 
  the 
  center, 
  between 
  the 
  Lincoln 
  

   cluster 
  of 
  peaks 
  and 
  Homestake 
  Peak, 
  a 
  large 
  upheaval, 
  which 
  we 
  

   named 
  Mount 
  Arkansas.! 
  To 
  the 
  east 
  as 
  well 
  as 
  to 
  the 
  west 
  of 
  Mount 
  Ar- 
  

   kansas 
  lie 
  two 
  saddles, 
  about 
  4J 
  miles 
  apart 
  from 
  each 
  other, 
  where 
  the 
  

   two 
  principal 
  streams 
  rise 
  which 
  form 
  the 
  Eagle 
  Eiver 
  after 
  their 
  junc- 
  

   tion. 
  The 
  creek 
  starting 
  on 
  the 
  saddle 
  west 
  of 
  Mount 
  Arkansas 
  is 
  

   called 
  Tennessee 
  Fork, 
  because 
  this 
  saddle 
  is 
  also 
  called 
  Teunessee 
  

   Pass.l 
  

  

  The 
  creek 
  coming 
  from 
  the 
  eastern 
  saddle 
  has 
  the 
  name 
  of 
  Maiu 
  

   Pork 
  of 
  Eagle 
  Eiver, 
  from 
  the 
  fact 
  that 
  the 
  main 
  valley 
  of 
  the 
  Eagle 
  

   Eiver 
  can 
  be 
  traced 
  in 
  that 
  direction 
  nearly 
  up 
  to 
  its 
  source.§ 
  After 
  a 
  

   flow 
  of 
  6 
  miles, 
  the 
  two 
  young 
  branches 
  of 
  the 
  Eagle 
  Eiver 
  unite 
  at 
  a 
  

   poiut 
  7 
  miles 
  north 
  of 
  Mount 
  Arkansas. 
  Where 
  the 
  two 
  branches 
  Ibrm 
  

   a 
  junction, 
  the 
  Eagle 
  Eiver 
  assumes 
  already 
  the 
  shape 
  of 
  a 
  valley 
  and 
  

   retains 
  the 
  same 
  for 
  a 
  distance 
  of 
  4 
  miles. 
  ; 
  

  

  The 
  valley-bottom 
  is 
  here 
  sometimes 
  one-half 
  mile 
  in 
  width, 
  but 
  bor- 
  1 
  

   dered 
  on 
  both 
  sides 
  with 
  steep 
  walls 
  which 
  rise 
  over 
  1,(K10 
  feet 
  within 
  one- 
  

   quarter 
  of 
  a 
  mile 
  from 
  their 
  base. 
  The 
  bordering 
  of 
  Eagle 
  Eiver 
  on 
  the 
  

   east 
  is 
  caused 
  from 
  spurs 
  coming 
  from 
  the 
  Eagle 
  Eiver 
  Mountains 
  and 
  

   on 
  the 
  west 
  from 
  spurs 
  coming 
  from 
  Homestake 
  Peak. 
  

  

  The 
  side 
  streams 
  that 
  issue 
  from 
  Eagle 
  Eiver 
  Mountains 
  on 
  the 
  east 
  

   enter 
  the 
  Eagle 
  Eiver 
  at 
  right 
  angles 
  and 
  flow 
  through 
  narrow 
  gulches 
  

   before 
  entering 
  the 
  valley 
  of 
  the 
  latter. 
  After 
  meandering 
  for 
  4 
  miles 
  in 
  a 
  

   spacious 
  valley. 
  Eagle 
  Eiver 
  is 
  pressed 
  into 
  an 
  absolute 
  canon, 
  in 
  which 
  

   it 
  remains 
  for 
  3 
  miles, 
  and 
  baffling 
  the 
  attempt 
  of 
  men 
  to 
  follow 
  it 
  

   through 
  its 
  mountainous 
  character. 
  At 
  the 
  lower 
  end 
  of 
  this 
  caiion 
  

  

  i 
  

  

  * 
  See 
  main 
  crest 
  of 
  rauge. 
  

  

  tSee 
  Ml 
  )unfc 
  Arkansas, 
  crest 
  of 
  maiu 
  range. 
  

  

  t 
  See 
  Tennessee 
  Pass, 
  crest 
  of 
  main 
  range. 
  

  

  § 
  This 
  branch 
  shows 
  evidence 
  by 
  its 
  structure 
  of 
  being 
  tbe 
  main 
  valley. 
  

  

  