﻿PLIOCENE 
  PERIOD 
  IN 
  ENGLAND. 
  67-"> 
  

  

  wick 
  and 
  the 
  ridges 
  described 
  by 
  Mr. 
  Jukes-lirowne. 
  This 
  water 
  

   is 
  represented 
  in 
  Map 
  6 
  by 
  the 
  unshaded 
  spaces 
  in 
  Sheets 
  45, 
  4(3, 
  

   47, 
  51, 
  52, 
  64, 
  65. 
  and 
  70, 
  and 
  the 
  sea- 
  water 
  by 
  lines. 
  The 
  ice 
  

   is 
  shown 
  as 
  still 
  issuing 
  by 
  the 
  (reversed) 
  valley 
  of 
  the 
  Trent 
  to 
  the 
  

   western 
  sea, 
  hut 
  as 
  having 
  retreated 
  from 
  all 
  the 
  other 
  issues 
  : 
  the 
  

   parting 
  between 
  the 
  Trent 
  and 
  Weaver 
  systems 
  being 
  between 
  

   800 
  and 
  900 
  feet 
  below 
  the 
  elevation 
  of 
  the 
  gravel 
  of 
  the 
  great 
  

   submergence 
  with 
  molluscan 
  remains 
  at 
  Minora 
  Mountain, 
  winch 
  

   is 
  little 
  more 
  than 
  30 
  miles 
  west 
  of 
  that 
  parting, 
  and 
  800 
  feet 
  

   below 
  that 
  with 
  these 
  remains 
  near 
  Macclesfield, 
  at 
  a 
  less 
  distance 
  

   north 
  of 
  it, 
  this 
  part 
  of 
  England 
  was 
  still 
  submerged. 
  

  

  The 
  sheet 
  of 
  gravel 
  in 
  the 
  valley 
  of 
  the 
  Ivel, 
  a 
  tributary 
  of 
  the 
  

   Great 
  Ouse, 
  which 
  rises 
  to 
  about 
  140 
  feet 
  above 
  O. 
  D., 
  near 
  Biggles- 
  

   wade, 
  and 
  which, 
  in 
  the 
  first 
  part 
  of 
  this 
  memoir 
  (p. 
  482), 
  I 
  

   doubted 
  being 
  the 
  gravel 
  c, 
  is 
  probably 
  part 
  of 
  the 
  gravel 
  thus 
  

   arising 
  from 
  the 
  blocking-up 
  of 
  the 
  Great-Quse 
  valley 
  ; 
  and 
  that 
  

   part 
  of 
  the 
  gravel 
  not 
  overlain 
  by 
  the 
  Chalky 
  Clay 
  in 
  the 
  valleys 
  of 
  

   the 
  AVelland 
  and 
  Nen 
  and 
  their 
  tributaries, 
  which 
  is 
  much 
  above 
  

   the 
  level 
  of 
  the 
  rivers, 
  has 
  also, 
  I 
  think, 
  originated 
  from 
  this 
  cause; 
  

   for 
  as 
  the 
  depression 
  traced 
  in 
  Stage 
  YI. 
  only 
  raised 
  the 
  marine 
  ex- 
  

   tremity 
  of 
  the 
  Wash 
  rivers 
  some 
  30 
  feet 
  above 
  its 
  present 
  elevation, 
  

   it 
  could 
  not 
  have 
  raised 
  the 
  water-level 
  of 
  these 
  rivers 
  to 
  any 
  greater 
  

   extent: 
  and 
  though 
  the 
  increased 
  precipitation, 
  which 
  I 
  propose 
  to 
  

   show 
  accompanied 
  that 
  depression, 
  probably 
  raised 
  this 
  level 
  further, 
  

   it 
  does 
  not 
  appear 
  to 
  me 
  that 
  it 
  could 
  have 
  done 
  so 
  to 
  the 
  extent 
  

   indicated 
  in 
  the 
  foregoing 
  description, 
  nor 
  would 
  the 
  position 
  of 
  the 
  

   Cyrt 
  ->w- 
  formation 
  at 
  Barnwell 
  be 
  consistent 
  with 
  it. 
  

  

  Although 
  during 
  the 
  emergence 
  a 
  gradual 
  recovery 
  from 
  the 
  

   southerly 
  and 
  westerly 
  increments 
  of 
  depression 
  was 
  going 
  on. 
  yet, 
  

   unless 
  there 
  was 
  no 
  upward 
  movement 
  at 
  all 
  in 
  the 
  eastern 
  direction 
  

   after 
  Norfolk 
  and 
  North 
  Suffolk 
  had 
  emerged, 
  this 
  emergence 
  must 
  

   have 
  extended 
  England 
  in 
  the 
  direction 
  of 
  the 
  North 
  Sea 
  beyond 
  its 
  

   present 
  limit. 
  This 
  we 
  shall 
  see 
  it 
  did, 
  and 
  also 
  that 
  the 
  subsequent 
  

   phenomena 
  show 
  that 
  the 
  present 
  relative 
  inclination 
  of 
  the 
  east 
  

   and 
  west 
  sides 
  of 
  England 
  was 
  not 
  fully 
  attained 
  until 
  after 
  the 
  

   second 
  (or 
  minor) 
  giaciation 
  ; 
  but 
  when, 
  by 
  the 
  complete 
  disappear- 
  

   ance 
  of 
  the 
  ice 
  of 
  the 
  first 
  (or 
  major) 
  giaciation 
  from 
  their 
  neigh- 
  

   bourhood, 
  the 
  four 
  AVash 
  valleys, 
  already 
  referred 
  to, 
  ceased 
  to 
  be 
  

   blocked 
  up 
  by 
  it. 
  as 
  well 
  as 
  received 
  no 
  water 
  from 
  this 
  source, 
  they 
  

   became 
  occupied 
  only 
  by 
  the 
  surface-drainage 
  of 
  their 
  respective 
  

   catchment 
  areas 
  : 
  and 
  their 
  rivers 
  thus 
  resulting 
  (save 
  to 
  the 
  extent 
  

   to 
  which 
  their 
  flatter 
  fall 
  and 
  the 
  greater 
  distance 
  of 
  their 
  mouths 
  at 
  

   this 
  time 
  may 
  have 
  raised 
  their 
  surface 
  by 
  retarding 
  their 
  flow) 
  ran 
  

   at 
  the 
  same 
  level 
  as 
  they 
  now 
  do 
  : 
  for 
  as 
  they 
  have 
  no 
  exeava 
  ting- 
  

   power 
  now, 
  but, 
  on 
  the 
  contrary, 
  have 
  filled 
  their 
  valleys 
  with 
  one 
  

   unvarying 
  sheet 
  of 
  alluvial 
  mud, 
  a 
  fortiori 
  they 
  could 
  have 
  had 
  

   none 
  when 
  their 
  fall 
  was 
  less. 
  

  

  The 
  same 
  remark 
  applies 
  to 
  the 
  Thames 
  and 
  all 
  other 
  English 
  

   rivers 
  draining 
  eastwards, 
  save 
  that 
  their 
  valleys 
  never 
  were 
  blocked 
  

   up 
  by 
  the 
  ice, 
  and 
  the 
  level 
  of 
  the 
  fresh 
  water 
  in 
  them 
  thus 
  raised. 
  

  

  