﻿86 
  

  

  A. 
  C. 
  RAMSAY 
  ON 
  THE 
  PHYSICAL 
  HISTORY 
  

  

  Ei 
  

  

  fea 
  

  

  <*2 
  

  

  I 
  

  

  60 
  

  

  5 
  s 
  

  

  §02 
  

  

  a 
  o 
  

  

  502 
  feet 
  above 
  the 
  average 
  level 
  of 
  the 
  river 
  at 
  the 
  bridge 
  of 
  Basel. 
  

  

  Assuming, 
  as 
  the 
  data 
  seem 
  to 
  warrant, 
  that 
  the 
  basin 
  of 
  Basel 
  and 
  

   Mainz 
  was 
  filled 
  with 
  Miocene 
  strata 
  to 
  a 
  height 
  

   of 
  more 
  than 
  300 
  feet 
  at 
  Basel 
  above 
  the 
  present 
  

   plain 
  of 
  the 
  Bhine, 
  there 
  was 
  still 
  ample 
  fall 
  for 
  

   the 
  river 
  springing 
  from 
  the 
  end 
  of 
  the 
  old 
  Bhine 
  

   glacier, 
  or 
  even 
  at 
  a 
  later 
  date 
  from 
  the 
  level 
  of 
  

   the 
  Lake 
  of 
  Constance, 
  for 
  the 
  Bhine 
  to 
  have 
  

   flowed 
  along 
  the 
  inclined 
  plain 
  of 
  Miocene 
  rocks 
  

   that, 
  at 
  levels 
  of 
  at 
  least 
  from 
  300 
  to 
  500 
  feet 
  

   above 
  the 
  present 
  plain, 
  once 
  extended 
  from 
  

   Basel 
  to 
  Mainz 
  and 
  the 
  neighbourhood 
  of 
  Bin- 
  

   gen. 
  I 
  have 
  already 
  stated 
  that 
  the 
  present 
  

   fall 
  from 
  Basel 
  to 
  Mainz 
  is 
  531 
  feet. 
  In 
  the 
  

   older 
  epoch 
  adverted 
  to, 
  even 
  aUowing 
  the 
  Mio- 
  

   cene 
  strata 
  of 
  Mainz 
  to 
  have 
  attained 
  a 
  height 
  

   of 
  500 
  feet 
  above 
  the 
  level 
  of 
  the 
  present 
  plain, 
  

   there 
  may 
  still 
  have 
  been 
  a 
  fall 
  in 
  the 
  river- 
  

   channel 
  on 
  the 
  surface 
  of 
  the 
  ancient 
  plain 
  of 
  

   more 
  than 
  300 
  feet 
  between 
  Basel 
  and 
  Bingen. 
  

   This 
  is 
  equal 
  to 
  about 
  1 
  foot 
  9 
  inches 
  per 
  mile, 
  

   an 
  inclination 
  amply 
  sufficient 
  to 
  have 
  carried 
  

   forward 
  at 
  a 
  rapid 
  rate 
  the 
  waters 
  of 
  the 
  Bhine. 
  

   At 
  this 
  epoch 
  of 
  the 
  history 
  of 
  the 
  river, 
  the 
  

   general 
  arrangement 
  of 
  the 
  rocks 
  must 
  have 
  

   been 
  somewhat 
  of 
  the 
  kind 
  shown 
  in 
  fig. 
  1. 
  

  

  In 
  this 
  manner 
  I 
  consider 
  that 
  it 
  must 
  have 
  

   happened 
  that 
  the 
  river 
  originally 
  flowed 
  along 
  

   the 
  surface 
  of 
  a 
  high 
  inclined 
  plain 
  of 
  Miocene 
  

   strata 
  that 
  then 
  filled 
  the 
  valley 
  of 
  the 
  Bhine, 
  

   from 
  the 
  confines 
  of 
  Switzerland 
  to 
  what 
  is 
  

   now 
  the 
  southern 
  end 
  of 
  the 
  gorge. 
  When 
  this 
  

   system 
  of 
  drainage 
  began, 
  the 
  deep 
  river-gorge 
  

   that 
  now 
  separates 
  the 
  Taunus 
  and 
  the 
  Hunds- 
  

   ruck 
  had 
  no 
  existence 
  (see 
  Map, 
  fig. 
  2). 
  The 
  

   hilly 
  slopes 
  on 
  either 
  side 
  were, 
  so 
  to 
  speak, 
  un- 
  

   broken 
  ; 
  and 
  a 
  mere 
  minor 
  shaUow 
  valley, 
  the 
  

   bottom 
  of 
  which 
  was 
  as 
  high 
  as 
  the 
  edge 
  of 
  the 
  

   present 
  gorge, 
  received 
  and 
  carried 
  northward 
  

   the 
  waters 
  of 
  the 
  Bhine. 
  By 
  degrees 
  the 
  great 
  

   river 
  flowing 
  at 
  this 
  high 
  level 
  began 
  to 
  scoop 
  

   out 
  a 
  channel, 
  which 
  graduaUy 
  deepened 
  and 
  

   became 
  bounded 
  by 
  cliffs. 
  Just 
  in 
  proportion 
  

   as 
  the 
  channel 
  of 
  the 
  gorge 
  deepened, 
  so 
  the 
  

   Bhine, 
  wandering 
  through 
  the 
  long 
  inclined 
  

   plain 
  of 
  Miocene 
  rocks 
  between 
  Basel 
  and 
  Bin- 
  

   gen, 
  by 
  degrees 
  had 
  its 
  surface-level 
  lowered 
  

   through 
  the 
  ordinary 
  processes 
  of 
  watery 
  ero- 
  

   sion. 
  The 
  wide 
  aUuvial 
  flat 
  through 
  which 
  the 
  

   river, 
  studded 
  with 
  islands, 
  now 
  flows, 
  shows 
  

  

  s? 
  § 
  

  

  ■3 
  o 
  o 
  

  

  2 
  ®» 
  

  

  tM. 
  

  

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