﻿712 
  SEAELES 
  V. 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  And 
  of 
  those 
  geologists 
  who 
  attribute 
  such 
  features 
  to 
  atmospheric 
  

   agency, 
  I 
  would 
  ask, 
  "Why 
  does 
  that 
  agency, 
  which 
  is 
  common 
  to 
  

   the 
  whole 
  surface, 
  operate 
  in 
  this 
  selective 
  way, 
  removing 
  gravel 
  

   and 
  brickearth 
  from 
  great 
  spaces 
  and 
  leaving 
  it 
  intact 
  in 
  others, 
  the 
  

   formation 
  on 
  which 
  these 
  rest 
  in 
  both 
  parts 
  being 
  the 
  same 
  ? 
  Not 
  

   only 
  has 
  the 
  denuding 
  agency 
  so 
  operated, 
  but 
  it 
  has, 
  along 
  with 
  the 
  

   removed 
  gravel 
  and 
  brickearth, 
  carried 
  off 
  considerable 
  thicknesses 
  of 
  

   the 
  formation 
  on 
  which 
  these 
  rested, 
  though 
  of 
  the 
  diverse 
  character 
  

   which 
  clay, 
  marl, 
  sand, 
  and 
  chalk 
  present 
  to 
  the 
  denuding 
  action. 
  

  

  Thus, 
  it 
  appears 
  to 
  me, 
  both 
  the 
  Cyrena-ioimation 
  and 
  the 
  gravel 
  

   r/ 
  have, 
  within 
  the 
  eastern 
  part 
  of 
  the 
  Thames 
  valley, 
  been 
  subjected 
  

   to 
  much 
  disturbance. 
  This, 
  when 
  that 
  valley 
  was 
  covered 
  by 
  water 
  

   up 
  to 
  the 
  elevations 
  at 
  which 
  remnants 
  of 
  4 
  occur 
  (which 
  is 
  

   near 
  100 
  feet 
  at 
  Grays, 
  and 
  quite 
  that 
  by 
  Dartford 
  Heath, 
  and 
  pro- 
  

   portionately 
  higher 
  west 
  of 
  London 
  and 
  up 
  the 
  Lea 
  valley), 
  began 
  

   with 
  the 
  rise 
  from 
  the 
  depression 
  which 
  I 
  have 
  traced 
  in 
  this 
  stage, 
  

   and 
  throwing 
  this 
  water 
  against 
  the 
  east 
  side 
  of 
  the 
  Lea 
  valley, 
  

   washed 
  away 
  from 
  there 
  the 
  gravel 
  /, 
  on 
  which 
  the 
  C;?/mi«-formation 
  

   had 
  rested, 
  as 
  well 
  as 
  that 
  formation 
  also 
  : 
  and 
  acting 
  upon 
  the 
  

   wider 
  space 
  described 
  in 
  the 
  east 
  of 
  Sheet 
  1*, 
  washed 
  this 
  away 
  

   from 
  that 
  part 
  also. 
  A 
  similar 
  disturbance, 
  repeated 
  after 
  the 
  pause 
  

   in 
  the 
  rise 
  had 
  allowed 
  the 
  gravel 
  g 
  to 
  accumulate, 
  washed 
  away 
  

   that 
  gravel 
  also 
  from 
  the 
  same 
  areas, 
  at 
  least 
  above 
  the 
  present 
  

   Marsh-level 
  ; 
  and 
  looking 
  at 
  the 
  wide 
  spaces 
  from 
  which 
  the 
  sand 
  

   and 
  gravel 
  within 
  the 
  limit 
  up 
  to 
  which 
  the 
  depression 
  of 
  the 
  

   <7?/mirt-formation 
  must, 
  in 
  South 
  Hampshire, 
  have 
  extended, 
  to 
  cor- 
  

   respond 
  with 
  its 
  position 
  in 
  Sussex, 
  has, 
  according 
  to 
  Mr. 
  Codring- 
  

   ton's 
  map 
  and 
  sections, 
  been 
  removed, 
  much 
  of 
  this 
  disturbance 
  and 
  

   denudation 
  must 
  have 
  prevailed 
  in 
  that 
  area 
  also. 
  

  

  The 
  formations 
  which 
  were 
  accumulated 
  during 
  the 
  rise 
  from 
  the 
  

   redepression 
  just 
  traced, 
  and 
  during 
  a 
  stationary 
  period 
  due 
  to 
  a 
  

   pause 
  in 
  such 
  rise, 
  I 
  proceed 
  to 
  trace 
  in 
  Stage 
  VII. 
  

  

  Stage 
  VII. 
  The 
  Minor 
  Glaciation, 
  or 
  Reindeer 
  -Period. 
  

  

  In 
  the 
  Journal 
  of 
  the 
  Society 
  for 
  1868, 
  p. 
  846, 
  Mr. 
  Eome 
  and 
  

   I 
  brought 
  to 
  the 
  notice 
  of 
  geologists 
  that 
  in 
  East 
  Lincolnshire 
  and 
  

   Yorkshire 
  there 
  occurred 
  a 
  clay 
  differing 
  in 
  character 
  from 
  the 
  

   general 
  mass 
  of 
  the 
  glacial 
  clay 
  of 
  that 
  region, 
  and 
  which 
  latter 
  the 
  

   Holderness-Cliff 
  section 
  showed 
  it 
  to 
  wrap 
  like 
  a 
  cloth. 
  Lor 
  this, 
  

   as 
  the 
  word 
  " 
  Upper 
  Boulder-clay 
  " 
  was 
  misleading, 
  from 
  its 
  having 
  

   been 
  applied 
  to 
  the 
  Chalky 
  Clay 
  to 
  distinguish 
  that 
  from 
  an 
  anterior 
  

   bed, 
  we 
  proposed 
  the 
  name 
  of 
  the 
  " 
  Hessle 
  Clay," 
  from 
  its 
  best-known 
  

   section 
  occurring 
  at 
  Hessle, 
  four 
  miles 
  west 
  of 
  Hull. 
  From 
  the 
  sub- 
  

   angular 
  condition 
  of 
  the 
  chalk 
  debris 
  in 
  this 
  clay, 
  so 
  different 
  from 
  

   the 
  very 
  rolled 
  character 
  of 
  that 
  debris 
  in 
  the 
  Basement 
  Clay 
  (B 
  of 
  

  

  * 
  The 
  water 
  seems 
  also 
  to 
  have 
  been 
  thrown 
  against 
  the 
  eastern 
  side 
  of 
  this 
  

   space 
  both 
  north 
  and 
  south 
  of 
  the 
  Thames, 
  see 
  figs. 
  XXX. 
  and 
  XXXI. 
  It 
  is 
  im- 
  

   possible 
  to 
  say 
  to 
  what 
  extent 
  sand 
  representing 
  part 
  of 
  the 
  Cyrgwa-formation 
  

   may 
  have 
  escaped 
  this 
  denudation, 
  and 
  be 
  mixed 
  up 
  with 
  the 
  gravel 
  /shown 
  in 
  

   the 
  lines 
  of 
  section 
  which 
  I 
  have 
  given 
  across 
  the 
  Thames 
  and 
  Lea 
  valleys. 
  

  

  

  