﻿Dawson 
  — 
  Elevation 
  of 
  the 
  Rocky 
  Mountain 
  Range. 
  463 
  

  

  Akt. 
  XL. 
  — 
  Note 
  on 
  the 
  amount 
  of 
  Elevation 
  which 
  has 
  taken 
  

   place 
  along 
  the 
  Rocky 
  Mountain 
  Range 
  in 
  British 
  America 
  

   since 
  the, 
  close 
  of 
  the 
  Cretaceous 
  period; 
  by 
  Dr. 
  G. 
  M. 
  

   Dawson. 
  (Reply 
  of 
  March 
  18 
  to 
  a 
  letter 
  from 
  J. 
  D. 
  Dana.) 
  

  

  Between 
  latitudes 
  49° 
  and 
  52° 
  (or 
  thereabouts) 
  numerous 
  

   infolds 
  of 
  Cretaceous 
  rocks 
  occur 
  in 
  the 
  Rocky 
  Mountains 
  

   proper, 
  or 
  Eastern 
  range 
  of 
  the 
  Cordillera. 
  (Laramide 
  Range.) 
  

   These 
  consist 
  chiefly 
  of 
  earlier 
  Cretaceous 
  (Kootanie) 
  but 
  in 
  

   places 
  strata 
  as 
  high 
  up 
  as 
  Lower 
  Laramie 
  (St. 
  Mary 
  River 
  

   beds) 
  still 
  remain. 
  The 
  actual 
  elevation 
  of 
  _ 
  these 
  rocks 
  is 
  now 
  

   in 
  many 
  places 
  from 
  6000 
  to 
  8000 
  feet 
  above 
  sea-level. 
  In 
  the 
  

   adjacent 
  belt 
  of 
  foothills, 
  to 
  the 
  east, 
  the 
  same 
  Cretaceous 
  

   rocks 
  are 
  found, 
  but 
  here 
  still 
  including 
  strata 
  as 
  high 
  as 
  Upper 
  

   Laramie. 
  The 
  actual 
  elevation 
  is 
  here 
  often 
  between 
  5000 
  and 
  

   6000 
  feet 
  above 
  sea-level. 
  

  

  In 
  the 
  mountains, 
  the 
  Cretaceous 
  rocks 
  have 
  been 
  involved 
  in 
  

   all 
  the 
  flexure, 
  faulting 
  and 
  overthrust 
  suffered 
  by 
  the 
  Palaeo- 
  

   zoic 
  ; 
  and 
  both 
  in 
  the 
  mountains 
  and 
  foothills 
  these 
  rocks 
  are 
  

   found 
  at 
  all 
  angles 
  up 
  to 
  vertical 
  and 
  even 
  overturned. 
  

  

  It 
  is 
  thus 
  difficult 
  to 
  know 
  to 
  what 
  elevations 
  these 
  rocks 
  

   may 
  have 
  been 
  thrust 
  up 
  in 
  some 
  places, 
  but 
  a 
  minimum 
  esti- 
  

   mate 
  may 
  be 
  arrived 
  at 
  by 
  tracing 
  the 
  continuations 
  of 
  the 
  

   beds 
  over 
  the 
  less 
  disturbed 
  anticlinals 
  or 
  by 
  adding 
  their 
  volume 
  

   to 
  the 
  elevation 
  of 
  flat-lying 
  ranges 
  of 
  the 
  older 
  rocks. 
  About 
  

   latitude 
  50° 
  it 
  may 
  thus 
  be 
  shown 
  that 
  the 
  hase 
  of 
  the 
  Cretace- 
  

   ous 
  must 
  in 
  several 
  places 
  have 
  considerably 
  exceeded 
  10,000 
  

   in 
  altitude, 
  while 
  in 
  Mr. 
  McConnell's 
  section 
  along 
  Bow 
  Pass 
  

   (51° 
  15') 
  to 
  the 
  north 
  of 
  Devil's 
  Lake, 
  the 
  same 
  horizon 
  must 
  

   have 
  been 
  about 
  15,500 
  feet 
  above 
  sea-level, 
  the 
  beds 
  at 
  this 
  

   place 
  being 
  nearly 
  flat. 
  

  

  To 
  ascertain 
  the 
  uplift 
  of 
  the 
  beds 
  which 
  were 
  at 
  sea-level 
  at 
  

   the 
  close 
  of 
  the 
  Cretaceous, 
  the 
  volume 
  of 
  the 
  Cretaceous 
  strata 
  

   must 
  of 
  course 
  be 
  added 
  to 
  such 
  figures 
  as 
  the 
  above. 
  This 
  was, 
  

   in 
  the 
  eastern 
  part 
  of 
  the 
  mountains, 
  at 
  least 
  17,000 
  feet 
  and 
  

   may 
  well 
  have 
  been 
  20,000 
  feet 
  (See 
  G-. 
  S. 
  C. 
  Report, 
  1885, 
  p. 
  

   166 
  B), 
  giving 
  as 
  a 
  minimum 
  estimate 
  of 
  greatest 
  uplift 
  for 
  the 
  

   region 
  say 
  32,000 
  to 
  35,000 
  feet. 
  

  

  Farther 
  north, 
  Cretaceous 
  infolds 
  in 
  the 
  Rocky 
  Mountains 
  

   become 
  less 
  common, 
  so 
  far 
  as 
  known, 
  but 
  the 
  foothills 
  retain 
  

   the 
  same 
  general 
  character 
  to 
  Peace 
  River 
  and 
  beyond. 
  Proba- 
  

   bly 
  the 
  uplift 
  was 
  somewhat 
  less 
  in 
  these 
  latitudes, 
  as 
  the 
  

   Rocky 
  Mountain 
  range 
  proper 
  is 
  less 
  important 
  and 
  narrower. 
  

  

  Still 
  farther 
  north, 
  opposite 
  the 
  Mackenzie 
  delta, 
  Mr. 
  

   McConnell 
  describes 
  the 
  range 
  as 
  composed 
  in 
  its 
  highest 
  part 
  

  

  Air. 
  Jour. 
  Scl— 
  Third 
  Series, 
  Vol. 
  XLIX, 
  No. 
  294.— 
  June, 
  1895. 
  

   31 
  

  

  