﻿50 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  on 
  the 
  west, 
  with 
  the 
  ends 
  of 
  the 
  beds 
  thrown 
  down, 
  dragged 
  up. 
  

   This 
  is 
  the 
  structure 
  from 
  station 
  32 
  eastward 
  to 
  the 
  Gunnison. 
  

  

  North 
  of 
  Unaweep 
  Canon 
  the 
  east 
  and 
  west 
  sides 
  of 
  the 
  plateau 
  ap- 
  

   pear 
  to 
  be 
  more 
  nearly 
  alike, 
  and 
  we 
  have 
  a 
  dragged 
  fault 
  on 
  both 
  sides. 
  

   Going 
  north 
  from 
  the 
  canon, 
  however, 
  we 
  find 
  a 
  monoclinal 
  fold 
  with 
  an 
  

   east 
  and 
  west 
  axis, 
  and 
  the 
  Grand 
  Eiver 
  is 
  in 
  a 
  canon 
  cut 
  in 
  the 
  red 
  

   beds, 
  while 
  hogbacks 
  of 
  'No. 
  1 
  Cretaceous, 
  dipping 
  northward, 
  are 
  seen 
  

   on 
  the 
  north 
  side 
  of 
  the 
  river. 
  (Fig. 
  1, 
  plate 
  II.) 
  We 
  see, 
  therefore, 
  

   that 
  the 
  monoclinal 
  folds 
  are 
  modified 
  at 
  various 
  points. 
  From 
  the 
  ex- 
  

   posures 
  noted 
  in 
  the 
  numerous 
  caiions 
  it 
  is 
  evident 
  that 
  the 
  red 
  beds 
  

   (Trias 
  1) 
  are 
  superimposed 
  to 
  the 
  granitein 
  the 
  Uncompahgre 
  plateau. 
  

   West 
  of 
  the 
  crest 
  Carboniferous 
  strata 
  are 
  seen, 
  and 
  overlapping 
  similar 
  

   to 
  that 
  along 
  the 
  eastern 
  edge 
  of 
  the 
  Front 
  range 
  is 
  noticed, 
  and 
  the 
  

   similarity 
  of 
  the 
  fold 
  is 
  apparent, 
  although 
  along 
  the 
  Front 
  range 
  we 
  

   have 
  no 
  faulting. 
  The 
  abrupt 
  fold 
  in 
  both 
  cases 
  is 
  noted 
  near 
  the 
  line 
  

   of 
  overlapping 
  of 
  the 
  Carboniferous 
  by 
  the 
  Trias, 
  the 
  greatest 
  elevation 
  

   occurring 
  where 
  the 
  least 
  thickness 
  of 
  strata 
  occurs. 
  The 
  mode 
  of 
  

   action 
  in 
  both 
  cases 
  is 
  probably 
  the 
  same, 
  although 
  the 
  amount 
  of 
  

   elevation 
  in 
  the 
  Uncompahgre 
  plateau 
  is 
  far 
  less 
  than 
  that 
  in 
  the 
  Front 
  

   range. 
  As 
  to 
  the 
  age 
  of 
  the 
  elevation 
  of 
  the 
  Uncompahgre 
  plateau 
  we 
  

   have 
  no 
  clew, 
  but 
  the 
  probability 
  is 
  that 
  it 
  was 
  synchronous 
  with 
  the 
  

   Front 
  range 
  and 
  Park 
  range. 
  

  

  