﻿PEAI.E.] 
  UNCOMPAHGRE 
  VALLEY. 
  ' 
  41 
  

  

  down 
  iu 
  the 
  geological 
  scale 
  as 
  the 
  Triassic. 
  The 
  peaks 
  south 
  of 
  the 
  

   narrow 
  mesa 
  (Tongue 
  Mesa) 
  just 
  described 
  show 
  beautifully 
  the 
  influence 
  

   of 
  the 
  character 
  of 
  rocks 
  upon 
  erosion. 
  The 
  valleys 
  were 
  once 
  probably 
  

   the 
  seat 
  of 
  glaciers, 
  although 
  the 
  rocks, 
  being 
  comparatively 
  soft, 
  post- 
  

   glacial 
  erosive 
  influences 
  have 
  removed 
  the 
  traces 
  to 
  a 
  great 
  extent. 
  

   The 
  peaks 
  range 
  in 
  elevation 
  from 
  11,000 
  to 
  14,000 
  feet, 
  and 
  during 
  

   the 
  melting 
  of 
  the 
  snows 
  in 
  the 
  spring 
  great 
  changes 
  must 
  be 
  made 
  

   owing 
  to 
  the 
  increased 
  force 
  of 
  the 
  streams, 
  fed 
  from 
  the 
  accumulated 
  

   snows 
  of 
  the 
  preceding 
  winter. 
  

  

  Between 
  the 
  Eastern 
  branch 
  (Rio 
  de 
  las 
  Vacas) 
  and 
  the 
  main 
  Uucom- 
  

   pahgre 
  is 
  a 
  broad 
  strip 
  of 
  rolling 
  country, 
  gradually 
  becoming 
  steeper 
  as 
  

   we 
  approach 
  the 
  mountains. 
  Kear 
  the 
  forks 
  it 
  assumes 
  a 
  mesa-like 
  char- 
  

   acter, 
  the 
  sand-stones 
  of 
  the 
  Dakota 
  group 
  (Cretaceous 
  No. 
  1) 
  forming 
  the 
  

   tops 
  of 
  the 
  tables, 
  which 
  are 
  about 
  500 
  feet 
  above 
  the 
  level 
  of 
  the 
  streams. 
  

   Before 
  reaching 
  the 
  hills, 
  however, 
  higher 
  beds 
  are 
  seen, 
  and 
  their 
  soft 
  

   and 
  shaly 
  nature 
  causes 
  them 
  to 
  weather 
  into 
  rounded 
  hills, 
  which 
  are 
  

   characteristic 
  of 
  the 
  Middle 
  and 
  Upper 
  Cretaceous 
  strata 
  in 
  this 
  region 
  

   The 
  main 
  Uncompahgre 
  rises 
  in 
  the 
  Uncompahgre 
  Mountains, 
  be- 
  

   tween 
  the 
  head 
  of 
  the 
  San 
  Miguel 
  Eiver 
  and 
  the 
  Lake 
  Fork 
  of 
  the 
  

   Gunnison, 
  opposite 
  the 
  sources 
  of 
  the 
  Animas, 
  a 
  branch 
  of 
  the 
  San 
  

   Juan. 
  This 
  portion 
  of 
  the 
  river 
  is 
  described 
  by 
  Dr. 
  Endlich 
  in 
  his 
  re- 
  

   port 
  of 
  1874. 
  In 
  a 
  little 
  valley, 
  where 
  two 
  branches 
  join 
  before 
  the 
  river 
  

   leaves 
  the 
  mountains, 
  is 
  the 
  site 
  of 
  the 
  new 
  mining 
  town 
  Ouray. 
  Here 
  

   also 
  are 
  a 
  number 
  of 
  hot 
  springs. 
  The 
  rocks 
  are 
  mainly 
  Carboniferous, 
  

   i 
  ntersected 
  by 
  volcanic 
  dykes 
  and 
  lodes, 
  with 
  mineral 
  matter. 
  Emerging 
  

   from 
  the 
  mountains, 
  the 
  river 
  enters 
  what 
  is 
  called 
  Uncompahgre 
  Park. 
  

   This 
  is 
  a 
  small, 
  grassy 
  valley, 
  just 
  outside 
  of 
  the 
  mountains. 
  Before 
  

   reaching 
  this 
  park, 
  the 
  Carboniferous 
  beds 
  have 
  sunk 
  and 
  the 
  red 
  beds 
  ap- 
  

   pear, 
  dipping 
  to 
  the 
  north. 
  Above 
  them, 
  in 
  the 
  park, 
  is 
  the 
  Dakota 
  sand- 
  

   stone. 
  Next, 
  at 
  the 
  lower 
  end, 
  we 
  notice 
  the 
  Cretaceous 
  shales 
  abutting 
  

   against 
  the 
  Jurassic, 
  and 
  above 
  the 
  latter 
  the 
  Dakota 
  group. 
  There 
  is, 
  

   therefore, 
  at 
  this 
  point 
  a 
  fault. 
  From 
  the 
  park 
  the 
  stream 
  plunges 
  into 
  

   a 
  caSon 
  cut 
  through 
  Cretaceous 
  Dakota 
  sandstones. 
  Before 
  entering 
  

   this 
  canon, 
  a 
  branch 
  comes 
  in 
  from 
  the 
  west 
  at 
  right 
  angles 
  to 
  the 
  main 
  

   stream. 
  This 
  creek, 
  Dallas 
  Fork, 
  and 
  its 
  branches 
  have 
  several 
  park-like 
  

   openings. 
  The 
  mountains 
  just 
  south 
  here 
  present 
  a 
  steep 
  front 
  toward 
  

   the 
  north, 
  rising 
  in 
  many 
  places 
  in 
  sheer 
  precipices, 
  below 
  which 
  are 
  the 
  

   heads 
  of 
  the 
  creeks 
  which 
  unite 
  to 
  form 
  the 
  western 
  branch 
  of 
  the 
  Uncom- 
  

   pahgre. 
  The 
  principal 
  one 
  of 
  these 
  creeks 
  rises 
  on 
  the 
  northern 
  face 
  of 
  

   Mount 
  Sneffles. 
  The 
  course 
  of 
  the 
  Dallas 
  Fork, 
  which 
  receives 
  the 
  waters 
  

   of 
  these 
  creeks, 
  is 
  due 
  east. 
  It 
  follows 
  the 
  line 
  of 
  the 
  fault 
  which 
  has 
  been 
  

   referred 
  to, 
  and 
  which 
  will 
  be 
  more 
  fully 
  described 
  in 
  another 
  portion 
  of 
  

   the 
  report. 
  The 
  rocks 
  on 
  the 
  north 
  side 
  dip 
  to 
  the 
  northeast. 
  Between 
  

   the 
  branches 
  are 
  black 
  shales 
  (No. 
  4 
  Cretaceous) 
  and 
  yellow 
  sandstones. 
  

   The 
  stream 
  heads 
  in 
  a 
  beautiful, 
  grassy 
  plateau, 
  opposite 
  the 
  San 
  Miguel 
  

   Eiver, 
  and 
  joins 
  the 
  main 
  stream 
  at 
  the 
  foot 
  of 
  Uncompahgre 
  Park. 
  A 
  

   short 
  distance 
  above 
  the 
  mouth 
  of 
  Dallas 
  Fork 
  are 
  the 
  springs 
  which 
  

   give 
  the 
  name 
  of 
  Uncompahgre 
  — 
  red-water 
  spring 
  — 
  to 
  the 
  river 
  and 
  park. 
  

   They 
  are 
  warm, 
  and 
  surrounded 
  by 
  a 
  red 
  deposit, 
  consisting 
  mainly 
  of 
  

   iron 
  oxide. 
  

  

  The 
  Uncompahgre 
  enters 
  a 
  caGon 
  immediately 
  after 
  the 
  Dallas 
  Fork 
  

   unites 
  with 
  it. 
  The 
  walls 
  of 
  the 
  canon 
  here 
  are 
  from 
  700 
  to 
  800 
  feet 
  

   above 
  the 
  level 
  of 
  the 
  stream. 
  The 
  caiion 
  is 
  eight 
  miles 
  long, 
  and 
  is 
  for 
  

   the 
  most 
  part 
  a 
  narrow 
  valley. 
  There 
  are 
  a 
  few 
  open 
  spaces, 
  the 
  larg- 
  

   est, 
  where 
  the 
  eastern 
  branch, 
  Rio 
  de 
  las 
  Vacas, 
  comes 
  in, 
  about 
  five 
  miles 
  

  

  