﻿PLIOCENE 
  PERIOD 
  IN 
  ENGLAND. 
  729 
  

  

  the 
  Cyrena 
  yet 
  lingered 
  there, 
  however, 
  is 
  doubtful*. 
  If 
  it 
  be 
  

   present 
  in 
  the 
  fluvio-marine 
  base 
  of 
  the 
  sections 
  at 
  Menchecouft, 
  in 
  

   which 
  the 
  Cyrena 
  occurs, 
  it 
  must 
  have 
  done 
  so 
  ; 
  but, 
  as 
  I 
  have 
  

   pointed 
  out 
  in 
  the 
  case 
  of 
  the 
  gravel 
  g 
  overlying 
  the 
  Cyrena-sand 
  at 
  

   Uphall 
  field, 
  Ilford, 
  a 
  confusion 
  of 
  river-beds 
  of 
  distinct 
  ages 
  may 
  

   very 
  easily 
  occur. 
  

  

  The 
  passage 
  upwards 
  of 
  this 
  gravel 
  g 
  into 
  a 
  few 
  feet 
  of 
  brick- 
  

   earth 
  does 
  not 
  seem 
  to 
  occur, 
  in 
  the 
  Thames 
  valley, 
  in 
  those 
  parts 
  

   which 
  are 
  near 
  to 
  the 
  areas 
  from 
  which 
  this 
  gravel, 
  as 
  well 
  as 
  / 
  

   and 
  the 
  Cfyrewa-formation, 
  have 
  been 
  denuded 
  ; 
  and 
  this 
  doubtless 
  

   arises 
  from 
  the 
  partial 
  denudation 
  to 
  which 
  it 
  has 
  been 
  subjected 
  

   there 
  ; 
  but 
  the 
  uniform 
  way 
  in 
  which, 
  where 
  it 
  does 
  occur, 
  this 
  

   brickearth 
  is 
  distinct 
  from, 
  though 
  successional 
  to, 
  the 
  gravel 
  beneath 
  

   it, 
  shows 
  that 
  it 
  cannot 
  be 
  due, 
  as 
  has 
  been 
  suggested 
  in 
  the 
  case 
  

   of 
  brickearth 
  or 
  loess 
  generally, 
  to 
  floods 
  each 
  year 
  swelling 
  the 
  

   rivers 
  beyond 
  their 
  normal 
  gravel-depositing 
  condition 
  ; 
  for 
  were 
  it 
  so, 
  

   the 
  gravel 
  would 
  alternate 
  throughout 
  with 
  thin 
  seams 
  of 
  inundation- 
  

   mud, 
  instead, 
  as 
  is 
  the 
  case, 
  of 
  the 
  two 
  forming 
  distinct 
  beds. 
  The 
  

   presence 
  of 
  this 
  brickearth 
  in 
  a 
  thickness 
  varying 
  from 
  3 
  to 
  6 
  feet 
  

   over 
  and 
  yet 
  apparently 
  gradually 
  changing 
  in 
  to- 
  the 
  gravel, 
  proves 
  that 
  

   some 
  change 
  of 
  conditions 
  occurred 
  by 
  which 
  the 
  formation 
  of 
  gravel 
  

   gave 
  place 
  to 
  mud 
  : 
  and 
  it 
  seems 
  to 
  indicate 
  that 
  a 
  similar 
  change 
  took 
  

   place 
  in 
  climate, 
  as 
  the 
  minor 
  glaciation 
  waned, 
  to 
  that 
  which 
  took 
  

   place 
  as 
  it 
  came 
  on 
  ; 
  for 
  the 
  bed 
  no. 
  4 
  of 
  the 
  Cyr 
  ena-iormation 
  in 
  

   the 
  Thames 
  valley 
  exactly 
  resembles 
  this 
  brickearth 
  over 
  </, 
  and 
  

   succeeds 
  the 
  sand, 
  no. 
  3 
  of 
  that 
  formation, 
  in 
  exactly 
  the 
  same 
  way 
  

   in 
  which 
  this 
  brickearth 
  succeeds 
  the 
  gravel 
  g. 
  

  

  I 
  observed 
  in 
  connexion 
  with 
  the 
  Cfyrena-formation 
  that 
  bed 
  no. 
  4 
  

   of 
  it 
  seemed 
  to 
  indicate 
  that 
  a 
  great 
  flooding 
  of 
  the 
  land-surface 
  at 
  

   that 
  time 
  occurred, 
  which 
  filled 
  the 
  water 
  occupying 
  the 
  Thames 
  

   valley 
  with 
  mud, 
  and 
  so 
  gave 
  rise 
  by 
  its 
  precipitation 
  to 
  that 
  bed. 
  

   The 
  same 
  thing 
  appears 
  to 
  have 
  recurred 
  at 
  the 
  end 
  of 
  the 
  gravel 
  g 
  : 
  

   for 
  not 
  only 
  does 
  this 
  brickearth 
  over 
  it 
  indicate 
  this, 
  but 
  the 
  bed 
  

   y 
  in 
  Lincolnshire 
  (fig. 
  LIV.) 
  and 
  the 
  sands 
  which 
  I 
  have 
  referred 
  to 
  

   the 
  action 
  of 
  the 
  water 
  from 
  the 
  ice 
  of 
  the 
  Hessle 
  Clay, 
  and 
  shown 
  

   under 
  the 
  letters 
  Ty 
  in 
  fig. 
  L., 
  are 
  overlain 
  by 
  a 
  bed 
  which 
  T 
  can 
  

   only 
  refer 
  to 
  this 
  agency. 
  The 
  latter 
  consists 
  of 
  a 
  gravel 
  (gh) 
  

   several 
  feet 
  thick, 
  principally 
  made 
  up 
  of 
  fragments 
  of 
  the 
  hard 
  

   Yorkshire 
  chalk 
  worn 
  flat. 
  The 
  place 
  which 
  it 
  occupies 
  in 
  the 
  

   coast-section 
  shows 
  that 
  its 
  distribution 
  is 
  unconnected 
  with 
  the 
  

   sands 
  Ty, 
  on 
  which 
  it 
  rests, 
  and 
  that 
  it 
  is 
  a 
  sheet 
  that 
  has 
  been 
  

   formed 
  in 
  a 
  small 
  valley 
  which 
  stretches 
  from 
  Bridlington 
  up 
  to 
  

   the 
  Wold, 
  and 
  is 
  occupied 
  by 
  a 
  little 
  stream 
  called 
  the 
  Gipsey 
  Race. 
  

  

  that 
  gravel 
  being 
  stated 
  as 
  60 
  feet 
  above 
  the 
  Avon 
  ; 
  and 
  this 
  would 
  not, 
  propor- 
  

   tionately 
  to 
  the 
  sea-level 
  of 
  tho 
  time, 
  differ 
  much 
  from 
  that 
  indicated 
  by 
  the 
  

   shingle 
  in 
  the 
  Isle 
  of 
  Wight 
  Foreland 
  cliff. 
  The 
  skull 
  and 
  horns 
  of 
  a 
  Reindeer 
  arc 
  

   said 
  to 
  have 
  occurred 
  in 
  gravel 
  beneath 
  Boulder-clay 
  at 
  Xihnaurs, 
  in 
  Ayrshire 
  

   ('Journal,' 
  vol. 
  xxi. 
  p. 
  216). 
  This 
  gravel, 
  however, 
  may 
  have 
  been 
  contempo- 
  

   raneous 
  with 
  the 
  overlying 
  clay, 
  supposing 
  that 
  to 
  be 
  of 
  the 
  minor 
  glaciation, 
  in 
  

   the 
  same 
  way 
  as 
  the 
  gravel 
  c 
  is 
  with 
  the 
  Chalky 
  Clay. 
  

   * 
  See 
  note, 
  page 
  741. 
  

  

  Q.J.G.S. 
  No. 
  152. 
  3 
  c 
  

  

  