﻿PLIOCENE 
  PERIOD 
  IN 
  ENGLAND. 
  677 
  

  

  (Kentish) 
  Stour 
  at 
  elevations 
  up 
  to 
  250 
  feet 
  within 
  the 
  chalk 
  escarp- 
  

   ment. 
  

  

  East 
  of 
  the 
  line 
  of 
  fig. 
  VI. 
  which 
  accompanies 
  the 
  first 
  part 
  of 
  this 
  

   memoir, 
  in 
  which 
  figure 
  it 
  is 
  shown 
  at 
  elevations 
  between 
  80 
  and 
  

   100 
  feet), 
  this 
  gravel 
  /' 
  occupies 
  lower 
  and 
  lower 
  elevations, 
  termi- 
  

   nating 
  eastwards, 
  on 
  the 
  north 
  side 
  of 
  the 
  Thames, 
  in 
  the 
  low 
  escarp- 
  

   ments 
  of 
  West 
  Tilbury 
  in 
  fig. 
  XXXII. 
  and 
  Fobbing 
  in 
  fig. 
  XXX. 
  These 
  

   escarpments 
  face 
  the 
  Thames 
  or 
  its 
  creeks 
  ; 
  but 
  from 
  its 
  eastern 
  

   extremity 
  at 
  Fobbing 
  this 
  gravel 
  crowns 
  an 
  escarpment 
  which 
  rises 
  

   towards 
  Romford 
  (near 
  which 
  town 
  it 
  is 
  crossed 
  by 
  the 
  line 
  of 
  fig. 
  

   XXXIII. 
  ), 
  and 
  faces 
  the 
  side 
  of 
  the 
  valley, 
  as 
  shown 
  by 
  figs. 
  VI. 
  and 
  

   XXIX., 
  which 
  cross 
  it 
  in 
  this 
  part. 
  Where 
  it 
  thus 
  faces 
  inland, 
  

   this 
  escarpment 
  attains 
  an 
  elevation 
  of 
  117 
  feet 
  ; 
  and 
  as 
  the 
  elevation 
  

   rises, 
  the 
  space 
  between 
  the 
  escarpment 
  and 
  the 
  valley-side, 
  against 
  

   which 
  the 
  gravel 
  originally 
  rested, 
  diminishes 
  from 
  the 
  six 
  miles 
  

   shown 
  in 
  fig. 
  VI. 
  until, 
  just 
  west 
  of 
  the 
  line 
  of 
  fig. 
  XXXIII., 
  it 
  lies 
  

   undisturbed 
  against 
  the 
  valley-side, 
  which 
  it 
  continues 
  to 
  do 
  from 
  

   thence 
  westwards 
  to 
  the 
  Lea 
  river, 
  up 
  the 
  vallej^ 
  of 
  which 
  it 
  ex- 
  

   tends 
  continuously, 
  until, 
  inosculating 
  with 
  c 
  and 
  e 
  (in 
  the 
  south- 
  

   west 
  of 
  Sheet 
  47 
  and 
  south-east 
  of 
  46), 
  it 
  passes 
  both 
  under 
  and 
  over 
  

   the 
  Chalky 
  Clay. 
  As 
  it 
  thus 
  stretches 
  up 
  the 
  Lea 
  valley, 
  however, 
  

   from 
  Tottenham 
  to 
  the 
  part 
  where 
  it 
  passes 
  under 
  the 
  Chalky 
  Clay 
  

   in 
  the 
  south-west 
  of 
  Sheet 
  47, 
  it 
  occupies 
  the 
  western 
  slope 
  only 
  of 
  the 
  

   valley, 
  as 
  shown 
  in 
  fig. 
  XXXI 
  X. 
  

  

  On 
  the 
  south 
  side 
  of 
  the 
  Thames 
  this 
  gravel 
  rises 
  at 
  Wimbledon 
  

   Common 
  and 
  Richmond 
  Park 
  to 
  elevations 
  of 
  170 
  and 
  181 
  feet 
  ; 
  and 
  

   there 
  also 
  it 
  terminates 
  in 
  the 
  direction 
  of 
  the 
  valley-side 
  in 
  an 
  

   escarpment, 
  as 
  shown 
  in 
  fig. 
  XXVIII., 
  several 
  miles 
  intervening 
  be- 
  

   tween 
  this 
  escarpment 
  and 
  the 
  valley- 
  side 
  up 
  to 
  which 
  it 
  must 
  once 
  

   have 
  lain. 
  West 
  of 
  the 
  line 
  of 
  fig. 
  XXVIII. 
  it, 
  for 
  the 
  most 
  part, 
  

   lies 
  up 
  to 
  the 
  valley-side, 
  both 
  north 
  and 
  south 
  of 
  the 
  Thames, 
  

   as 
  shown 
  in 
  fig. 
  XXXVIII. 
  , 
  though 
  over 
  most 
  of 
  the 
  south 
  part 
  it 
  

   has 
  been 
  so 
  much 
  removed 
  as 
  to 
  show 
  itself 
  only 
  in 
  patches, 
  as 
  

   represented 
  in 
  Sheet 
  7 
  of 
  Map 
  3. 
  This 
  map 
  is 
  a 
  careful 
  reduction 
  

   from 
  all 
  Sheets 
  7, 
  1, 
  2, 
  and 
  the 
  southern 
  portions 
  of 
  46, 
  47, 
  and 
  48 
  

   of 
  the 
  Ordnance 
  one-inch-to-the-mile 
  map 
  ; 
  and 
  upon 
  it 
  are 
  deli- 
  

   neated 
  the 
  gravels 
  c 
  and 
  e, 
  f, 
  and 
  g 
  ; 
  but 
  it 
  must 
  be 
  borne 
  in 
  mind 
  

   that, 
  owing 
  to 
  the 
  water 
  of 
  the 
  Oyrena-formation, 
  described 
  in 
  the 
  

   sequel, 
  having 
  risen 
  to 
  the 
  level 
  up 
  to 
  which 
  most 
  of 
  the 
  gravel 
  / 
  

   remains, 
  the 
  sand 
  which 
  constitutes 
  bed 
  3 
  of 
  that 
  formation 
  may 
  

   be 
  more 
  or 
  less 
  un 
  distinguishable 
  from 
  it, 
  and 
  thus 
  may 
  in 
  places 
  

   form 
  a 
  portion 
  of 
  what, 
  both 
  in 
  the 
  map 
  and 
  in 
  some 
  of 
  the 
  lines 
  of 
  

   section 
  which 
  I 
  have 
  given 
  across 
  it, 
  is 
  represented 
  as 
  gravel/; 
  for 
  

   it 
  is 
  only 
  where 
  brickfields 
  occur, 
  either 
  in 
  beds 
  2 
  or 
  4 
  of 
  it, 
  

   that 
  the 
  Cfy^wa-formation 
  can 
  be 
  shown. 
  The 
  scale 
  of 
  Map 
  3 
  

   does 
  not 
  admit 
  of 
  the 
  delineation 
  of 
  the 
  small 
  patches 
  of 
  the 
  gravel 
  

   V 
  which 
  have 
  escaped 
  destruction, 
  nor, 
  without 
  obscuring 
  the 
  

   other 
  features 
  necessary 
  for 
  my 
  explanations, 
  of 
  the 
  delineation 
  

   of 
  the 
  Chalky 
  Clay 
  ; 
  but 
  the 
  distribution 
  over 
  it 
  of 
  that 
  clay 
  may 
  be 
  

   seen 
  by 
  comparing 
  it 
  with 
  the 
  corresponding 
  part 
  of 
  Map 
  No. 
  2, 
  

  

  