﻿346 
  EEPOET 
  UNITED 
  STATES 
  GEOLOGICAL 
  SDRYEY. 
  

  

  reach 
  it. 
  liTeither 
  can 
  it 
  be 
  irrigated 
  by 
  artesian 
  wells, 
  as 
  the 
  dip 
  of 
  

   the 
  strata 
  is 
  away 
  from 
  it. 
  It 
  must 
  remain 
  what 
  it 
  is 
  ntterly 
  valueless, 
  

   unless 
  a 
  change 
  of 
  climate 
  takes 
  place. 
  

  

  The 
  Grand 
  River 
  Valley 
  is 
  limited 
  ou 
  the 
  north 
  by 
  the 
  Eoan 
  or 
  Book 
  

   Cliffs. 
  The 
  first 
  name 
  has 
  been 
  given 
  them 
  from 
  their 
  prevailing 
  color, 
  

   the 
  second 
  from 
  the 
  characteristic 
  shape 
  of 
  the 
  cliff", 
  which, 
  with 
  its 
  

   overhauging 
  crest 
  and 
  slight 
  talus, 
  bears 
  considerable 
  resemblance 
  to 
  

   the 
  edge 
  of 
  a 
  bound 
  book. 
  

  

  The 
  line 
  of 
  these 
  cliff's 
  extends 
  almost 
  unbroken 
  from 
  longitude 
  107° 
  

   45' 
  westward 
  across 
  the 
  Green 
  Eiver. 
  The 
  western 
  limit 
  has 
  not 
  yet 
  

   been 
  determined. 
  The 
  general 
  course 
  is 
  slightly 
  south 
  of 
  west, 
  gener- 
  

   ally 
  following 
  the 
  line 
  of 
  the 
  Grand, 
  being 
  at 
  a 
  greater 
  or 
  less 
  distance 
  

   from 
  it 
  as 
  the 
  river 
  trends 
  more 
  to 
  the 
  southward 
  or 
  northward. 
  These 
  

   cliffs 
  are 
  but 
  the 
  southern 
  escarpment 
  of 
  a 
  gently-inclined 
  plateau, 
  

   sloping 
  north 
  or 
  northeast 
  toward 
  White 
  Eiver. 
  With 
  the 
  exception 
  

   of 
  two 
  large 
  branches 
  of 
  the 
  Grand, 
  which, 
  near 
  the 
  eastern 
  end 
  of 
  the 
  

   cliffs, 
  cut 
  some 
  distance 
  back 
  into 
  the 
  plateau, 
  the 
  edge 
  of 
  the 
  cliffs 
  

   forms 
  the 
  divide 
  between 
  the 
  waters 
  of 
  the 
  Grand 
  and 
  White. 
  

  

  Above 
  the 
  mouth 
  of 
  Eoan 
  Creek 
  the 
  cliffs 
  are 
  simple 
  walls 
  of 
  rock, 
  

   nearly 
  A^ertical, 
  with 
  the 
  crest 
  only 
  three 
  or 
  four 
  miles 
  from 
  the 
  river. 
  

   Their 
  height 
  is 
  about 
  8,600 
  feet, 
  or 
  3,500 
  feet 
  above 
  the 
  river. 
  I^Torth 
  

   of 
  the 
  western 
  end 
  of 
  Grand 
  Mesaj 
  the 
  cliffs 
  send 
  off' 
  southward 
  a 
  

   heavy 
  spur, 
  dipping 
  at 
  a 
  low 
  angle 
  toward 
  the 
  northeast. 
  This 
  spur 
  

   joins 
  the 
  slopes 
  of 
  the 
  Grand 
  Mesa, 
  and 
  across 
  it 
  the 
  Grand 
  Eiver 
  has 
  

   cut 
  its 
  way 
  in 
  a 
  direction 
  the 
  reverse 
  of 
  the 
  dip, 
  making 
  a 
  tremendous 
  

   caQon, 
  which 
  reaches, 
  in 
  the 
  deepest 
  part, 
  a 
  depth 
  of 
  nearly 
  3,000 
  feet. 
  

  

  Farther 
  westward 
  the 
  cliffs 
  consist 
  of 
  very 
  rugged 
  and 
  iH'ecipitoiis 
  

   foot-hills, 
  rising 
  by 
  a 
  succession 
  of 
  broken 
  steps 
  to 
  the 
  crest. 
  

  

  In 
  this 
  part 
  the 
  crest 
  is 
  8,000 
  to 
  9,000 
  feet 
  high, 
  very 
  narrow 
  and 
  

   winding. 
  On 
  one 
  side 
  are 
  sheer 
  precipices, 
  several 
  hundreds 
  of 
  feet 
  in 
  

   height, 
  at 
  the 
  bases 
  of 
  which 
  head 
  small 
  branches 
  of 
  the 
  Grand. 
  On 
  

   the 
  other 
  side, 
  on 
  the 
  sloping 
  plateau 
  surface, 
  branches 
  ot 
  the 
  White 
  

   Eiver 
  head. 
  These 
  streams 
  rapidly 
  cut 
  their 
  way 
  down 
  in 
  the 
  soio 
  

   sandstones, 
  so 
  that 
  their 
  progress 
  northward 
  is 
  little 
  more 
  rapid 
  than 
  

   that 
  downward. 
  The 
  divide 
  is 
  in 
  many 
  places 
  not 
  more 
  than 
  30 
  or 
  40 
  

   feet 
  in 
  width, 
  with 
  a 
  sheer 
  cliff" 
  many 
  hundreds 
  of 
  feet 
  high 
  on 
  the 
  south 
  

   and 
  on 
  the 
  north 
  an 
  earth-slope 
  of 
  at 
  least 
  30°. 
  

  

  On 
  the 
  crest 
  water 
  is 
  very 
  scarce. 
  A 
  heavy 
  trail 
  winds 
  along 
  it, 
  and 
  

   at 
  every 
  12 
  or 
  15 
  miles 
  there 
  is 
  a 
  spring 
  of 
  excellent 
  water. 
  

  

  The 
  crest 
  is 
  mainly 
  covered 
  with 
  grass 
  and 
  sage; 
  quaking-aspen 
  

   groves 
  are 
  found 
  here 
  and 
  there, 
  and, 
  in 
  a 
  few 
  localities, 
  spruces 
  and 
  

   pines. 
  

  

  The 
  following 
  heights 
  are 
  on 
  the 
  crest 
  of 
  the 
  cliffs 
  : 
  

  

  Approximate 
  Aprosir.iate 
  Elevation, 
  

  

  latitude. 
  longitude. 
  Feet. 
  

  

  Station 
  16 
  39.11 
  109.38 
  8,787 
  

  

  Station 
  17 
  39.15 
  109.32 
  8,620 
  

  

  Station 
  18 
  39.19 
  109.32 
  8,758 
  

  

  Station 
  19 
  39.22 
  109.26 
  8,207 
  

  

  Station 
  20 
  39.25 
  109.10 
  8,368 
  

  

  Station 
  21 
  39.26 
  109.17 
  8,379 
  

  

  Station 
  22 
  39.26 
  109.06 
  8,051 
  

  

  Station 
  23 
  39.31 
  109.02 
  7,904 
  

  

  Station 
  24 
  39.32 
  109.00 
  8,681 
  

  

  Station 
  25 
  39.37 
  108.54 
  8,669 
  

  

  Station 
  26 
  39.36 
  108.49 
  8,770 
  

  

  Station 
  27 
  39.32 
  108.37 
  8,850 
  

  

  Station 
  28 
  39.25 
  108.37 
  8,431 
  

  

  Station 
  29 
  39.27 
  108.37 
  8,591 
  

  

  Station 
  30 
  39.24 
  108.35 
  8,571 
  

  

  