﻿464 
  Dawson 
  — 
  Elevation 
  of 
  the 
  Rocky 
  Mountain 
  Range. 
  

  

  of 
  Cretaceous 
  rocks, 
  but 
  there 
  only 
  about 
  4000 
  feet 
  above 
  the 
  

   sea. 
  Several 
  thousand 
  feet 
  have 
  doubtless 
  been 
  removed 
  by 
  

   denudation, 
  but 
  we 
  have 
  no 
  exact 
  knowledge 
  of 
  the 
  thickness 
  

   of 
  the 
  Cretaceous 
  in 
  that 
  region. 
  

  

  There 
  are 
  also 
  some 
  evidences 
  of 
  slight 
  or 
  moderate 
  uplift 
  

   in 
  the 
  Rocky 
  Mountains 
  proper 
  of 
  Alberta 
  previous 
  to 
  or 
  dur- 
  

   ing 
  the 
  Laramie, 
  such 
  as 
  the 
  supply 
  of 
  material 
  from 
  the 
  red 
  

   rocks 
  of 
  the 
  Triassic 
  to 
  the 
  middle 
  zone 
  of 
  the 
  Laramie, 
  opposite 
  

   that 
  part 
  of 
  the 
  range 
  in 
  which 
  these 
  rocks 
  occur, 
  (see 
  G. 
  S. 
  C. 
  

   Report, 
  1882-84, 
  p. 
  113 
  C.) 
  as 
  well 
  as 
  in 
  the 
  materials 
  of 
  the 
  

   older 
  Cretaceous 
  conglomerates, 
  although 
  these 
  last 
  may 
  in 
  part 
  

   have 
  been 
  derived 
  from 
  elevations 
  west 
  of 
  the 
  Laramide 
  Range. 
  

  

  It 
  is 
  probably 
  impossible 
  to 
  ascertain 
  exactly 
  how 
  long 
  the 
  

   main 
  uplifting 
  process 
  continued 
  or 
  to 
  what 
  extent 
  its 
  effect 
  was 
  

   counteracted 
  by 
  concurrent 
  denudation, 
  but 
  some 
  facts 
  may 
  be 
  

   cited 
  in 
  this 
  connection. 
  — 
  No 
  deposits 
  referable 
  to 
  the 
  Eocene, 
  

   as 
  distinct 
  from 
  the 
  Laramie, 
  have 
  been 
  found 
  in 
  the 
  foothills 
  

   or 
  over 
  the 
  Great 
  Plains 
  of 
  Western 
  Canada. 
  It 
  is 
  probable 
  

   that 
  none 
  such 
  exist, 
  and 
  it 
  may 
  therefore 
  be 
  assumed 
  that 
  free 
  

   eastward 
  drainage, 
  without 
  arrest, 
  obtained 
  during 
  this 
  period. 
  

   In 
  the 
  Early 
  Miocene 
  (White 
  River) 
  we 
  find 
  evidence 
  that 
  

   strong 
  rivers 
  were 
  carrying 
  coarse 
  gravels 
  from 
  the 
  mountains 
  

   out 
  over 
  the 
  plains 
  to 
  a 
  depression 
  some 
  200 
  miles 
  east 
  of 
  the 
  

   present 
  base 
  of 
  the 
  mountains, 
  forming 
  there 
  a 
  deposit 
  of 
  

   which 
  outliers, 
  like 
  that 
  of 
  the 
  Cypress 
  Hills, 
  still 
  remain. 
  

   These 
  deposits, 
  in 
  their 
  relation 
  to 
  the 
  Laramide 
  Range, 
  

   resemble 
  the 
  Upper 
  Siwalik 
  Conglomerates 
  of 
  India, 
  and 
  it 
  is 
  

   probable 
  that 
  at 
  this 
  time 
  a 
  range 
  comparable 
  to 
  the 
  Himalayas 
  

   in 
  height, 
  bordered 
  the 
  Great 
  Plains 
  of 
  Alberta 
  on 
  the 
  west. 
  

  

  During 
  the 
  Eocene 
  and 
  Miocene, 
  orographic 
  uplift 
  may 
  

   have 
  been 
  continuous, 
  but 
  sometime 
  long 
  before 
  the 
  close 
  of 
  

   the 
  Pliocene 
  it 
  came 
  to 
  an 
  end. 
  Evidence 
  of 
  this 
  is 
  found 
  in 
  

   the 
  following 
  circumstances. 
  — 
  The 
  Oldman, 
  Highwood, 
  Bow 
  

   and 
  other 
  rivers 
  flowing 
  from 
  the 
  mountains, 
  occupy 
  notably 
  

   wider 
  valleys 
  where 
  they 
  cross 
  the 
  eastern 
  foothill 
  belt. 
  In 
  

   these 
  valleys 
  Cretaceous 
  and 
  Laramie 
  rocks, 
  arranged 
  often 
  in 
  

   compressed 
  and 
  complicated 
  folds, 
  are 
  cut 
  sharply 
  off 
  on 
  planes 
  

   nearly 
  corresponding 
  with 
  the 
  slopes 
  of 
  the 
  present 
  streams 
  

   and 
  upon 
  the 
  basset 
  edges 
  of 
  these 
  rocks 
  bowlder-clay 
  and 
  other 
  

   glacial 
  deposits 
  are 
  spread. 
  Since 
  the 
  Glacial 
  period, 
  the 
  

   streams 
  have 
  cut 
  out 
  narrow 
  new 
  trenches 
  in 
  the 
  floors 
  of 
  these 
  

   valleys. 
  The 
  main 
  valleys 
  are 
  therefore 
  not 
  only 
  pre-glacial, 
  

   but 
  also 
  involve 
  a 
  long 
  antecedent 
  period 
  of 
  erosion, 
  during 
  

   which 
  the 
  conditions 
  changed 
  little 
  if 
  at 
  all. 
  Had 
  orogenic 
  

   movements 
  continued 
  in 
  the 
  Pliocene, 
  the 
  flexed 
  Cretaceous 
  

   beds 
  of 
  the 
  foothills 
  (intimately 
  connected 
  with 
  the 
  general 
  

   folding 
  of 
  the 
  mountains) 
  must 
  have 
  participated 
  in 
  them, 
  and 
  

  

  