﻿340 
  EEPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  At 
  the 
  south 
  end, 
  where 
  the 
  protrusion 
  of 
  the 
  mass 
  of 
  the 
  Sau 
  Juan 
  

   .range 
  is 
  iirst 
  felt, 
  there 
  is 
  a 
  decided 
  rise, 
  followed 
  by 
  breaking 
  off 
  of 
  the 
  

   upper 
  beds, 
  leaving 
  a 
  saddle. 
  Station 
  15 
  is 
  on 
  the 
  south 
  end 
  of 
  the 
  

   ei'est. 
  Its 
  elevation 
  is 
  10,200 
  feet. 
  Just 
  south 
  of 
  it, 
  and 
  three 
  miles 
  

   away, 
  the 
  height 
  of 
  the 
  saddle 
  is 
  but 
  8,700 
  feet. 
  The 
  saddle 
  contin- 
  

   ues 
  south 
  with 
  about 
  this 
  height 
  for 
  half 
  a 
  dozen 
  miles, 
  and 
  then 
  the 
  

   mountains 
  rise 
  abruptly 
  to 
  an 
  altitude 
  of 
  13,000 
  to 
  14,000 
  feet, 
  presenting 
  

   a 
  magnitieent 
  array 
  of 
  cliffs 
  and 
  peaks. 
  They 
  rise 
  in 
  single 
  slopes 
  to 
  

   the 
  highest 
  summits 
  without 
  any 
  foot-hilis 
  and 
  secondary 
  summits 
  which 
  

   elsewhere 
  so 
  dwarf 
  the 
  loftiest 
  peaks. 
  

  

  IsTowhere 
  is 
  the 
  influence 
  of 
  elevation 
  on 
  the 
  character 
  of 
  the 
  vegeta- 
  

   tion 
  more 
  plaiilly 
  marked 
  than 
  on 
  this 
  plateau. 
  In 
  the 
  interior, 
  near 
  

   the 
  crest, 
  the 
  land 
  is, 
  to 
  the 
  Utes, 
  oue 
  flowing 
  with 
  milk 
  and 
  honey. 
  

   Here 
  are 
  fine 
  streams 
  of 
  clear, 
  cold 
  water, 
  beautiful 
  aspen 
  groves, 
  the 
  

   best 
  of 
  grass 
  in 
  the 
  greatest 
  abundance, 
  and 
  a 
  profusion 
  of 
  wild 
  fruit 
  

   and 
  berries, 
  while 
  the 
  country 
  is 
  a 
  perfect 
  flower-garden. 
  This 
  ex- 
  

   tends 
  as 
  low 
  as 
  7,000 
  feet, 
  below 
  which 
  the 
  scene 
  changes 
  to 
  one 
  in 
  all 
  

   respects 
  the 
  reverse. 
  Aspen 
  gives 
  place 
  to 
  piiion 
  and 
  cedar. 
  The 
  

   grasses, 
  fruit, 
  and 
  flowers, 
  "to 
  sage, 
  cacti, 
  and 
  bare 
  rock. 
  The 
  streams 
  

   become 
  confined 
  in 
  rocky 
  caiions, 
  turn 
  muddy 
  and 
  warm, 
  and 
  gradually 
  

   disappear. 
  The 
  game 
  changes. 
  Black-tailed 
  deer 
  give 
  place 
  to 
  the 
  

   white-tailed 
  species. 
  Grouse 
  disappear, 
  while 
  rattlesnakes 
  and 
  cen- 
  

   tipedes 
  assert 
  their 
  proprietorship. 
  In 
  the 
  place 
  of 
  an 
  open, 
  rolling 
  

   country, 
  we 
  enter 
  a 
  district 
  traversed 
  by 
  deep, 
  narrow 
  gorges, 
  of 
  abrupt 
  

   precipices, 
  a 
  country 
  difticult 
  in 
  the 
  extreme 
  to 
  traverse, 
  without 
  a 
  

   knowledge 
  of 
  its 
  few 
  highways. 
  

  

  Geologically, 
  this 
  inclined 
  plateau 
  has 
  been 
  produced 
  by 
  a 
  gradual 
  

   rise 
  of 
  the 
  underlying 
  granite, 
  about 
  an 
  axis 
  in 
  the 
  Uncompahgre 
  Val- 
  

   ley, 
  carrying 
  with 
  it 
  the 
  sedimentary 
  beds. 
  The 
  thickness 
  of 
  the 
  latter 
  

   differ 
  in 
  different 
  places, 
  but 
  nowhere 
  on 
  the 
  plateau 
  does 
  it 
  exceed 
  

   1,000 
  feet. 
  

  

  Cutting 
  this 
  plateau 
  transversely 
  into 
  two 
  parts, 
  is 
  a 
  remarkable 
  top- 
  

   ographical 
  and 
  geological 
  feature 
  in 
  the 
  form 
  of 
  a 
  caiion, 
  which 
  con- 
  

   nects 
  the 
  Gunnison 
  on 
  the 
  northeast 
  with 
  the 
  Dolores 
  on 
  the 
  southwest. 
  

   It 
  enters 
  the 
  Gunnison 
  six 
  miles 
  above 
  its 
  mouth, 
  at 
  an 
  elevation 
  of 
  

   4,600 
  feet. 
  Following 
  it 
  southwestward, 
  its 
  bed 
  is 
  seen 
  to 
  rise 
  slowly, 
  

   with 
  a 
  stream 
  flowing 
  into 
  the 
  Gunnison, 
  while 
  the 
  walls 
  on 
  each 
  hand 
  

   rise 
  more 
  rapidly. 
  The 
  bottom 
  rises 
  to 
  a 
  divide, 
  with 
  an 
  elevation 
  of 
  

   7,000 
  feet, 
  several 
  miles 
  east 
  of 
  the 
  crest 
  of 
  tha 
  plateau. 
  The 
  walls 
  at 
  

   the 
  divide 
  have 
  an 
  elevation 
  of 
  1,200 
  feet. 
  West 
  of 
  this 
  divide, 
  there 
  

   is 
  a 
  stream 
  flowing 
  into 
  the 
  Dolores. 
  At 
  the 
  crest 
  of 
  the 
  plateau, 
  which 
  

   here 
  breaks 
  off 
  abruptly, 
  the 
  depth 
  of 
  the 
  caiion 
  is 
  fully 
  3,000 
  ieet. 
  Be- 
  

   yond 
  the 
  crest 
  the 
  walls 
  fall 
  off 
  abruptly 
  and 
  become 
  broken 
  up, 
  and 
  

   the 
  most 
  rapid 
  fall 
  in 
  the 
  bed 
  of 
  the 
  canon 
  is 
  here. 
  At 
  its 
  junction 
  

   with 
  the 
  Dolores, 
  about 
  12 
  miles 
  above 
  the 
  mouth 
  of 
  the 
  latter, 
  the 
  ele- 
  

   vation 
  is 
  4,618 
  feet, 
  or 
  the 
  same 
  as 
  at 
  the 
  junction 
  with 
  the 
  Gunnison. 
  

  

  Below 
  the 
  point 
  marked 
  "a" 
  on 
  the 
  accompanying 
  map, 
  the 
  caiion 
  is 
  

   narrow, 
  not 
  deep, 
  and 
  is 
  cut 
  in 
  soft 
  sedimentary 
  beds. 
  It 
  is 
  here 
  prob- 
  

   ably 
  the 
  work 
  of 
  the 
  small 
  stream 
  which 
  now 
  occupies 
  it. 
  At 
  "a" 
  

   granite 
  appears 
  on 
  the 
  bottoua, 
  and 
  thence 
  westward 
  the 
  lower 
  part 
  of 
  

   the 
  canon 
  is 
  cut 
  in 
  this, 
  evidently 
  by 
  a 
  powerful 
  stream. 
  The 
  granite 
  

   portion 
  of 
  the 
  walls 
  increases 
  in 
  height 
  as 
  the 
  caiion 
  deepens, 
  and 
  at 
  the 
  

   crest 
  of 
  the 
  plateau 
  forms 
  two-thirds 
  of 
  the 
  height 
  of 
  the 
  walls, 
  the 
  

   upper 
  third, 
  or 
  1,000 
  Ieet, 
  being 
  sedimentary 
  beds. 
  At 
  "i" 
  the 
  granite 
  

   suddenly 
  disappears. 
  The 
  caiion 
  is 
  narrow 
  near 
  the 
  Gunnison 
  end; 
  

   but 
  beyond 
  the 
  sharj) 
  elbow-like 
  bend 
  it 
  gradually 
  widens 
  as 
  far 
  as 
  the 
  

  

  