﻿PEALE.] 
  MESOZOIC 
  FORMATIONS 
  TRASSIC. 
  81 
  

  

  our 
  district 
  in 
  which 
  the 
  red 
  beds 
  have 
  never 
  been 
  present. 
  It 
  could 
  

   not 
  have 
  been 
  of 
  any 
  extent 
  north 
  and 
  south, 
  as 
  we 
  find 
  them 
  resting 
  

   on 
  the 
  granite 
  in 
  the 
  Grand 
  Caiion 
  of 
  the 
  Gunnison, 
  and 
  Dr. 
  Endlich 
  

   noted 
  the 
  existence 
  of 
  red 
  sandstones, 
  probably 
  of 
  the 
  same 
  age, 
  at 
  the 
  

   heads 
  of 
  the 
  southern 
  branches 
  of 
  the 
  Uncompahgre 
  and 
  Gunnison 
  

   Eivers, 
  a 
  distance 
  of 
  ten 
  or 
  twelve 
  miles 
  farther 
  south. 
  On 
  the 
  south 
  

   side 
  of 
  the 
  Gunnison, 
  between 
  these 
  points 
  I 
  found 
  several 
  places 
  where 
  

   Cretaceous 
  stata 
  rested 
  on 
  the 
  granite, 
  without 
  any 
  evidence 
  that 
  the 
  

   red 
  beds 
  had 
  ever 
  been 
  present 
  and 
  subsequently 
  removed 
  by 
  erosion. 
  

   The 
  gradual 
  thickening 
  of 
  the 
  series 
  as 
  we 
  go 
  westward 
  also 
  points 
  to 
  

   the 
  fact 
  of 
  there 
  having 
  been 
  land 
  in 
  this 
  portion 
  of 
  our 
  district 
  in 
  

   Triassic 
  times. 
  Toward 
  the 
  east 
  and 
  southeast, 
  the 
  area 
  may 
  have 
  been 
  

   larger. 
  In 
  New 
  Mexico, 
  however, 
  we 
  again 
  find 
  the 
  red 
  beds 
  resting 
  on 
  

   beds 
  containing 
  Carboniferous 
  fossils. 
  Northward, 
  we 
  have 
  to 
  go 
  only 
  

   as 
  far 
  as 
  the 
  Elk 
  Mountains 
  to 
  find 
  them. 
  Westward, 
  the 
  area 
  west 
  of 
  

   the 
  Uncompahgre 
  Eiver 
  is 
  probably 
  underlaid 
  with 
  them, 
  although 
  the 
  

   first 
  outcrop 
  is 
  not 
  seen 
  until 
  we 
  reach 
  the 
  crest 
  of 
  the 
  plateau 
  overlook- 
  

   ing 
  the 
  San 
  Miguel 
  Eiver. 
  I 
  shall 
  now 
  consider 
  the 
  series 
  as 
  it 
  occurs 
  at 
  

   different 
  points 
  throughout 
  the 
  district. 
  

  

  In 
  the 
  Grand 
  Canon 
  of 
  the 
  Gunnison 
  there 
  is 
  shown 
  only 
  a 
  narrow 
  

   belt 
  of 
  red 
  sandstone, 
  probably 
  the 
  upper 
  part 
  of 
  the 
  series, 
  resting 
  on 
  

   the 
  granitic 
  portion 
  of 
  the 
  chasm. 
  This 
  outcrop 
  thickens 
  as 
  we 
  follow 
  

   the 
  river 
  north, 
  and 
  southward 
  it 
  gradually 
  thins 
  out 
  and 
  disappears. 
  In 
  

   the 
  lower 
  canon 
  of 
  the 
  Gunnison, 
  about 
  150 
  feet 
  of 
  massive 
  red 
  and 
  pink 
  

   sandstone 
  borders 
  the 
  river. 
  

  

  In 
  the 
  area 
  between 
  Uuaweep 
  Canon, 
  Gunnison, 
  Uncompahgre, 
  and 
  

   San 
  Miguel 
  Eivers, 
  Triassic 
  rocks 
  form 
  the 
  surface 
  over 
  about 
  180 
  square 
  

   miles, 
  with 
  patches 
  of 
  Jurassic 
  shales 
  resting 
  upon 
  them. 
  As 
  we 
  go 
  

   southward, 
  the 
  Jurassic 
  disappears 
  beneath 
  the 
  Dakota 
  sandstone, 
  and 
  

   we 
  do 
  not 
  see 
  any 
  Triassic 
  until 
  we 
  reach 
  the 
  crest 
  of 
  the 
  plateau 
  where 
  

   the 
  red 
  beds 
  show 
  in 
  the 
  caSons 
  which 
  the 
  creeks 
  cut 
  as 
  they 
  flow 
  across 
  

   the 
  monoclinal 
  fold. 
  The 
  following 
  is 
  a 
  section 
  at 
  this 
  point: 
  

  

  Yellowish 
  sandstones. 
  

  

  Light-red 
  sandstones. 
  

  

  Blood-red 
  sandstones 
  and 
  shales. 
  

  

  Purplish 
  shales. 
  

  

  Following 
  the 
  crest 
  to 
  the 
  northwest, 
  we 
  find 
  the 
  overlying 
  beds 
  on 
  

   the 
  fold 
  removed, 
  and 
  the 
  red 
  beds 
  alone 
  continuous. 
  Still 
  farther 
  along 
  

   these 
  are 
  broken 
  and 
  probably 
  faulted 
  at 
  some 
  places. 
  On 
  the 
  plateau 
  

   they 
  dip 
  to 
  the 
  eastward 
  at 
  an 
  angle 
  of 
  4P 
  to 
  5°, 
  and 
  below 
  the 
  crest 
  

   the 
  inclination 
  is 
  60° 
  to 
  70° 
  to 
  the 
  westward. 
  This 
  decreases 
  toward 
  

   the 
  west, 
  and 
  the 
  red 
  beds 
  disappear 
  beneath 
  the 
  Jurassic 
  and 
  Creta- 
  

   ceous 
  beds 
  to 
  re-appear 
  at 
  the 
  top 
  of 
  .the 
  bluffs 
  along 
  the 
  Dolores 
  Eiver 
  

   with 
  Permian 
  ? 
  beds 
  beneath 
  them. 
  

  

  In 
  the 
  Unaweep 
  Caiion 
  the 
  red 
  beds 
  show 
  on 
  top 
  of 
  the 
  granite, 
  

   preserving 
  the 
  same 
  level 
  on 
  both 
  sides 
  of 
  the 
  canon. 
  The 
  dip 
  is 
  to 
  

   the 
  eastward, 
  and 
  the 
  outcrops 
  are 
  continuous 
  for 
  from 
  20 
  to 
  25 
  miles. 
  

   The 
  white 
  or 
  orange 
  colored 
  cross-bedded, 
  massive 
  sandstone 
  forms 
  the 
  

   top 
  of 
  the 
  series. 
  The 
  sandstones 
  below 
  are 
  more 
  laminated 
  than 
  they 
  

   are 
  on 
  the 
  Dolores. 
  Going 
  through 
  the 
  canon 
  from 
  east 
  to 
  west, 
  we 
  

   notice 
  a 
  gradual 
  thickening 
  of 
  the 
  strata. 
  At 
  station 
  40 
  it 
  is 
  270 
  feet. 
  

   At 
  38, 
  G 
  miles 
  farther 
  west, 
  it 
  is 
  342 
  feet, 
  and 
  west 
  of 
  station 
  34, 
  about 
  

   10 
  miles 
  farther, 
  the 
  thickness 
  is 
  between 
  500 
  and 
  600 
  feet, 
  while 
  across 
  

   the 
  Dolores 
  it 
  is 
  over 
  1,000 
  feet. 
  North 
  of 
  the 
  caiion 
  the 
  area 
  covered 
  

   by 
  the 
  red 
  beds 
  is 
  nearly 
  200 
  square 
  miles. 
  On 
  the 
  highest 
  part 
  of 
  the 
  

   Gas 
  

  

  