﻿724 
  SEARLES 
  V 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  ground 
  at 
  low 
  water. 
  Here 
  the 
  ice-floes, 
  bringing 
  the 
  blocks 
  of 
  

   hypersthene-rock 
  from 
  the 
  southward, 
  grounding 
  on 
  the 
  shallows 
  

   where 
  the 
  clay-gravel 
  (which 
  Mr. 
  Godwin- 
  Austen 
  says 
  contains 
  

   Littorince 
  and 
  fragments 
  of 
  Mytili) 
  was 
  accumulated, 
  left 
  these 
  on, 
  

   or 
  in, 
  that 
  gravel, 
  at 
  the 
  same 
  that 
  the 
  floes 
  packed 
  against 
  the 
  cliffs 
  

   to 
  the 
  east 
  and 
  west 
  of 
  this 
  flat 
  area. 
  By 
  the 
  rise 
  which 
  caused 
  the 
  

   sea 
  to 
  recede 
  from 
  these 
  cliff's, 
  the 
  sea 
  on 
  the 
  Selsea 
  coast 
  became 
  

   too 
  shallow 
  for 
  the 
  floes 
  to 
  pass, 
  and 
  the 
  clay-gravel 
  gave 
  place 
  to 
  a 
  

   more 
  littoral 
  gravel 
  with 
  sand 
  and 
  shingle, 
  with 
  shells 
  (c 
  of 
  the 
  

   diagram 
  at 
  page 
  708), 
  the 
  tidal 
  movement, 
  which 
  accompanied 
  

   this, 
  wearing 
  away 
  the 
  surface 
  of 
  the 
  clay-gravel. 
  Then, 
  by 
  

   the 
  continuance 
  of 
  the 
  rise, 
  this 
  became 
  land 
  ; 
  and 
  thereupon 
  it 
  

   was 
  overspread 
  by 
  the 
  same 
  atmospheric 
  formation 
  with 
  flint- 
  

   splinters 
  that 
  buries 
  the 
  cliffs 
  and 
  overlies 
  the 
  Avisford 
  sands, 
  

   viz. 
  b 
  of 
  the 
  diagram. 
  In 
  South 
  Lincolnshire 
  I 
  have 
  met 
  with 
  

   this 
  formation, 
  y, 
  capping 
  in 
  a 
  thickness 
  of 
  three 
  or 
  four 
  feet 
  

   the 
  Jurassic 
  limestone 
  of 
  that 
  county, 
  and 
  containing, 
  like 
  the 
  

   intrusive 
  cave-earth, 
  angular 
  fragments 
  of 
  the 
  limestone, 
  just 
  as 
  

   it 
  does 
  splinters 
  of 
  flint 
  where 
  it 
  occurs 
  in 
  the 
  vicinity 
  of 
  Chalk 
  ; 
  

   and 
  there 
  it 
  is 
  overlain 
  by 
  a 
  thin 
  bed 
  of 
  limestone 
  fragments 
  worn 
  

   flat 
  (see 
  bed 
  yr\ 
  of 
  fig. 
  LIV.). 
  All 
  this 
  part 
  of 
  England 
  during 
  the 
  

   major 
  glaciation 
  was 
  buried 
  beneath 
  the 
  land-ice 
  of 
  the 
  Chalky 
  Clay 
  

   (this 
  Clay, 
  though 
  not 
  covering 
  the 
  limestone 
  in 
  the 
  figure, 
  being 
  

   within 
  two 
  miles 
  of 
  it), 
  which 
  protected 
  the 
  surface 
  from 
  atmospheric 
  

   action, 
  when 
  the 
  islands 
  not 
  thus 
  protected 
  (not 
  merely 
  those 
  shown 
  

   in 
  Map 
  4, 
  but 
  those 
  formed 
  by 
  the 
  higher 
  eminences 
  of 
  the 
  Chalk 
  

   Downs 
  of 
  Kent, 
  Wiltshire, 
  &c), 
  by 
  being 
  subjected 
  to 
  it, 
  received 
  

   the 
  atmospheric 
  formation 
  of 
  clay 
  with 
  flints 
  which 
  covers 
  them. 
  

   The 
  medium 
  and 
  lower 
  elevations 
  of 
  the 
  South 
  and 
  West 
  of 
  England 
  

   were 
  at 
  the 
  same 
  time 
  protected 
  from 
  this 
  action 
  by 
  being 
  submerged, 
  

   so 
  that 
  it 
  is 
  only 
  to 
  the 
  frost 
  of 
  the 
  minor 
  glaciation 
  that 
  any 
  of 
  

   the 
  instances 
  which 
  I 
  have 
  given 
  of 
  this 
  formation 
  under 
  the 
  letter 
  y 
  

   can 
  apply. 
  

  

  In 
  his 
  sections 
  (at 
  pages 
  216 
  and 
  21 
  8 
  of 
  the 
  15th 
  volume 
  of 
  the 
  

   Journal), 
  Prof. 
  Prestwich 
  shows 
  the 
  Avisford 
  and 
  Waterbeach 
  sand 
  

   and 
  shingle, 
  which 
  I 
  have 
  referred 
  to 
  the 
  culmination 
  of 
  the 
  Cyrena- 
  

   formation 
  depression, 
  overlain 
  and 
  deeply 
  "ravined" 
  by 
  the 
  loam 
  

   with 
  angular 
  flint 
  fragments, 
  y, 
  which 
  I 
  consider 
  to 
  have 
  thus 
  

   originated 
  by 
  slide 
  from 
  the 
  chalk 
  of 
  the 
  contiguous 
  South 
  Downs 
  ; 
  

   and 
  he 
  shows 
  this 
  sand 
  and 
  shingle 
  cut 
  through 
  by 
  a 
  small 
  valley, 
  

   the 
  bottom 
  of 
  which 
  is 
  occupied 
  by 
  a 
  bed 
  of 
  gravel. 
  This 
  gravel 
  

   appears 
  to 
  me 
  to 
  be 
  g 
  of 
  this 
  memoir, 
  and 
  to 
  be 
  a 
  valley-bed 
  co 
  - 
  

   eval 
  with 
  this 
  loam, 
  in 
  the 
  same 
  way 
  that 
  y 
  in 
  fig. 
  XXVI. 
  is 
  the 
  

   fluviatile 
  equivalent 
  of 
  g 
  in 
  tig. 
  XXV. 
  This 
  Avisford 
  sand 
  and 
  shingle, 
  

   being 
  at 
  a 
  considerably 
  higher 
  elevation 
  than 
  the 
  foot 
  of 
  the 
  buried 
  

   cliffs 
  of 
  Brighton 
  and 
  the 
  Isle 
  of 
  Wight, 
  had 
  become 
  land 
  before 
  

   these 
  cliff's 
  had 
  come 
  into 
  existence 
  ; 
  and 
  the 
  small 
  valley 
  thus 
  cut 
  

   through 
  it, 
  and 
  occupied 
  by 
  g, 
  was 
  excavated 
  in 
  the 
  same 
  interval 
  

   in 
  which 
  the 
  break-up 
  and 
  denudation 
  of 
  the 
  Cyrena-foTm&tioTi 
  

   in 
  the 
  Thames 
  valley, 
  and 
  the 
  constitution 
  of 
  the 
  river-channel 
  in 
  

  

  