﻿HOLiviEs.] 
  LA 
  PLATA 
  VALLEY. 
  247 
  

  

  which 
  has 
  hardly 
  enough 
  vitality 
  to 
  clear 
  a 
  way 
  for 
  itself 
  through 
  the 
  

   encroaching 
  alluvium. 
  The 
  bright 
  meadows 
  and 
  the 
  heavy 
  vefdure 
  of 
  

   the 
  headwaters 
  have 
  been 
  replaced 
  by 
  sage 
  and 
  cactus 
  and 
  yellow 
  earth, 
  

   yet 
  the 
  valley 
  is 
  less 
  a 
  desert 
  than 
  might 
  at 
  first 
  be 
  suspected. 
  The 
  

   alluvial 
  bottoms 
  in 
  the 
  second 
  or 
  Bad 
  Land 
  valley 
  are 
  really 
  rich, 
  and 
  

   the 
  Weminuche 
  Utes 
  are 
  cultivating 
  crops 
  of 
  corn 
  and 
  vegetables. 
  The 
  

   fertile-looking 
  upper 
  valleys 
  are 
  quite 
  useless 
  for 
  agriculture, 
  on 
  account 
  

   of 
  the 
  high 
  altitude. 
  

  

  After 
  leaving 
  the 
  mountains 
  the 
  river 
  has 
  ascended, 
  geologically 
  

   speaking, 
  through 
  the 
  entire 
  Cretaceous 
  section, 
  but 
  the 
  exposures 
  are 
  

   rather 
  meager 
  and 
  measurements 
  not 
  reliable. 
  

  

  Below 
  the 
  Indian 
  farms 
  a 
  broad 
  valley 
  opens 
  out 
  to 
  the 
  right 
  and 
  

   left, 
  eroded 
  from 
  the 
  soft 
  formations 
  of 
  the 
  Bad 
  Land 
  Group. 
  It 
  

   extends 
  far 
  to 
  the 
  northeast, 
  following 
  the 
  strike 
  of 
  the 
  strata, 
  and 
  to 
  

   the 
  southwest 
  opens 
  out 
  in 
  a 
  low 
  passage-way 
  to 
  the 
  San 
  Juan. 
  For 
  

   nearly 
  10 
  miles 
  the 
  river 
  follows 
  this 
  depression, 
  but 
  instead 
  of 
  follow- 
  

   ing 
  it 
  through 
  between 
  the 
  Piiion 
  and 
  Verde 
  Mesas, 
  it 
  turns 
  to 
  the 
  left 
  

   and 
  cuts 
  directly 
  through 
  the 
  former, 
  forming 
  a 
  shallow 
  canon, 
  in 
  the 
  

   walls 
  of 
  which 
  the 
  sandstones 
  of 
  group 
  1, 
  general 
  section, 
  appear. 
  In 
  

   the 
  valley 
  above, 
  the 
  river 
  is 
  bordered 
  by 
  a 
  fine 
  system 
  of 
  terraces, 
  

   which 
  extends 
  over 
  many 
  square 
  miles 
  and 
  shows 
  a 
  number 
  of 
  well- 
  

   marked 
  levels 
  ; 
  the 
  highest 
  rises 
  to 
  200 
  or 
  300 
  feet 
  above 
  the 
  river. 
  On 
  

   a 
  subordinate 
  terrace, 
  near 
  the 
  river, 
  I 
  discovered 
  the 
  ruins 
  of 
  an 
  

   ancient 
  village. 
  Plans 
  and 
  descriptions 
  of 
  this 
  are 
  given 
  elsewhere. 
  

  

  The 
  greater 
  part 
  of 
  the 
  Piiion 
  Mesa 
  lies 
  to 
  the 
  west 
  of 
  the 
  La 
  Plata. 
  

   It 
  rises 
  gradually 
  from 
  the 
  river 
  toward 
  the 
  western 
  angle, 
  where 
  it 
  ter- 
  

   minates 
  in 
  a 
  high 
  promontory. 
  It 
  covers 
  an 
  area 
  of 
  some 
  40 
  square 
  

   miles 
  and 
  is 
  capped 
  with 
  a 
  massive 
  yellowish 
  or 
  light-brown 
  sandstone, 
  

   which 
  has 
  a 
  thickness 
  of 
  from 
  60 
  to 
  100 
  feet. 
  On 
  the 
  west 
  this 
  stratum 
  

   breaks 
  off 
  in 
  a 
  line 
  of 
  bold 
  and 
  picturesque 
  cliffs. 
  On 
  the 
  east 
  side 
  of 
  

   the 
  river 
  this 
  stratum 
  of 
  sandstone 
  lies 
  at 
  the 
  base 
  of 
  a 
  considerable 
  

   thickness 
  of 
  massive 
  sandstones, 
  which 
  constitute 
  group 
  1 
  of 
  the 
  general 
  

   section. 
  

  

  Beneath 
  the 
  sandstone 
  capping 
  of 
  the 
  mesa 
  are 
  the 
  Bad 
  Land 
  forma- 
  

   tions 
  (group 
  2, 
  general 
  section). 
  They 
  outcrop 
  all 
  around, 
  but 
  only 
  on 
  

   the 
  west 
  and 
  south 
  faces 
  are 
  the 
  Bad 
  Land 
  forms 
  well 
  developed. 
  Here 
  

   the 
  richly-colored, 
  soapy-looking 
  clays 
  are 
  weathered 
  into 
  a 
  thousand 
  

   fantastic 
  shapes, 
  and 
  broad 
  areas 
  have 
  neither 
  rocks 
  nor 
  vegetation 
  to 
  

   break 
  the 
  peculiarly 
  monotonous 
  waste. 
  This 
  group 
  I 
  have 
  identified 
  

   with 
  the 
  " 
  Puerco 
  marls" 
  of 
  Cope.* 
  

  

  Passing 
  down 
  to 
  the 
  west 
  over 
  this 
  belt 
  we 
  reach 
  the 
  depression 
  

   or 
  puerta 
  that 
  separates 
  the 
  PiSon 
  Mesa 
  from 
  Mesa 
  Verde. 
  Here 
  

   are 
  broad 
  flat 
  spaces 
  covered 
  with 
  grass 
  and 
  sage, 
  beyond 
  which 
  are 
  

   the 
  scattering 
  outcrops 
  of 
  the 
  Coal 
  Group 
  (3, 
  general 
  section). 
  First, 
  

   there 
  are 
  a 
  number 
  of 
  outcrops 
  of 
  yellow 
  and 
  rusty 
  sandstone, 
  and 
  

   following 
  these 
  the 
  outcrop 
  of 
  the 
  white 
  sandstone 
  which 
  lies 
  at 
  

   the 
  base 
  of 
  the 
  Coal 
  Group. 
  This 
  outcrop, 
  which 
  is 
  still 
  tipped 
  up 
  at 
  

   a 
  higher 
  angle 
  than 
  the 
  other 
  beds 
  by 
  the 
  San 
  Juan 
  fold, 
  may 
  be 
  

   traced 
  to 
  the 
  point 
  where 
  it 
  crosses 
  the 
  La 
  Plata 
  at 
  the 
  Indian 
  farms 
  

   and 
  beyond 
  to 
  Station 
  V, 
  while 
  to 
  the 
  south 
  it 
  can 
  be 
  followed 
  to 
  

   the 
  San 
  Juan, 
  where 
  it 
  falls 
  off 
  to 
  the 
  horizontal 
  and 
  forms 
  the 
  Pictured 
  

   Cliff's 
  (group 
  4, 
  general 
  section). 
  West 
  of 
  this 
  line 
  of 
  outcrop 
  we 
  cross 
  

   another 
  low 
  belt 
  and 
  then 
  begin 
  to 
  rise 
  on 
  the 
  slope 
  of 
  the 
  Mesa 
  Verde, 
  

   and 
  soon 
  encounter 
  the 
  cailon-cut 
  sandstones 
  of 
  the 
  Upper 
  Escarpment 
  

  

  *See 
  report 
  of 
  Chief 
  of 
  Etif);ineers 
  for 
  1875, 
  page 
  1012. 
  

  

  