﻿PLIOCENE 
  PERIOD 
  IN 
  ENGLA.NJD. 
  743 
  

  

  in 
  the 
  plate 
  to 
  Mi'. 
  Oodrington's 
  paper 
  in 
  vol. 
  xxvi. 
  of 
  the 
  Journal, 
  the 
  dis- 
  

   tinguishing 
  letters 
  being 
  substituted 
  to 
  agree 
  with 
  those 
  in 
  this 
  memoir. 
  

  

  The 
  lines 
  of 
  figs. 
  VI. 
  and 
  VII. 
  (in 
  the 
  Plate 
  to 
  the 
  first 
  part 
  of 
  this 
  memoir), 
  

   XXI., 
  XXII., 
  XXVII., 
  and 
  of 
  XXIX. 
  to 
  XLI. 
  are 
  shown 
  by 
  their 
  indicating 
  

   letters 
  on 
  Map 
  3 
  ; 
  and 
  that 
  of 
  fig. 
  XXVIII. 
  is 
  shown 
  in 
  part 
  on 
  that 
  map, 
  but 
  

   wholly 
  in 
  the 
  continuation 
  of 
  Map 
  2. 
  The 
  lines 
  of 
  figs. 
  I., 
  III., 
  V., 
  VI., 
  VII., 
  

   VIII. 
  , 
  IX. 
  and 
  XLII. 
  are 
  shown 
  by 
  their 
  distinguishing 
  letters 
  on 
  Map 
  2 
  or 
  

   its 
  continuation. 
  The 
  lines 
  of 
  figs. 
  I., 
  III., 
  V., 
  VI., 
  VII., 
  VIII. 
  and 
  IX., 
  are 
  

   also 
  shown 
  on 
  Map 
  1. 
  The 
  places 
  of 
  figs. 
  XLIIL, 
  XLIV., 
  those 
  of 
  XL 
  VI. 
  to 
  

   LTV., 
  and 
  those 
  of 
  the 
  cuts 
  Nos. 
  iv. 
  and 
  v., 
  are 
  shown 
  by 
  their 
  distinguishing 
  

   letters 
  on 
  Map 
  5, 
  and 
  that 
  of 
  fig. 
  LV. 
  on 
  the 
  continuation 
  of 
  Map 
  2. 
  Line 
  

   A 
  N 
  in 
  Map 
  3 
  is 
  that 
  of 
  Prof. 
  Hughes's 
  figure, 
  in 
  cut 
  No. 
  ii. 
  

  

  The 
  asterisk 
  in 
  Sheet 
  84 
  of 
  Map 
  4 
  indicates 
  the 
  part 
  where 
  the 
  Chalky 
  Clay 
  

   consists 
  of 
  reconstructed 
  chalk, 
  similar 
  to 
  the 
  material 
  of 
  which 
  most 
  of 
  the 
  

   masses 
  in 
  the 
  Contorted 
  Drift 
  in 
  North 
  Norfolk 
  are 
  composed. 
  

  

  The 
  letters 
  AP 
  have 
  by 
  inadvertence 
  been 
  used 
  to 
  indicate 
  one 
  thing 
  in 
  Map 
  5, 
  

   and 
  a 
  different 
  thing 
  in 
  the 
  continuation 
  of 
  Map 
  2 
  ; 
  but 
  the 
  references 
  to 
  them 
  

   in 
  the 
  body 
  of 
  the 
  memoir 
  will 
  prevent 
  any 
  confusion 
  between 
  them. 
  

  

  The 
  line 
  marking 
  on 
  Map 
  4 
  the 
  extreme 
  limit 
  of 
  the 
  Chalky 
  Clay 
  is 
  shown 
  

   as 
  continuous, 
  where 
  known 
  to 
  me 
  with 
  exactness, 
  and 
  as 
  broken 
  where 
  not 
  ; 
  but 
  

   in 
  Map 
  3 
  it 
  is, 
  though 
  exact, 
  a 
  broken 
  line. 
  The 
  islands 
  (partly 
  in 
  Sheet 
  46 
  and 
  

   partly 
  in 
  Sheet 
  47) 
  which 
  are 
  shown 
  in 
  Map 
  4 
  within 
  this 
  line, 
  were 
  not 
  over- 
  

   whelmed 
  by 
  the 
  Chalky 
  Clay 
  until 
  their 
  size 
  had 
  been 
  enlarged 
  by 
  emergence, 
  

   as 
  partly 
  shown 
  in 
  Map 
  2, 
  and 
  not 
  until 
  the 
  other 
  islands 
  shown 
  in 
  that 
  map 
  

   had 
  emei-ged. 
  The 
  islands 
  in 
  Sheets 
  46, 
  13, 
  and 
  7 
  of 
  Map 
  4, 
  not 
  thus 
  over- 
  

   whelmed, 
  are 
  covered 
  with 
  the 
  atmospheric 
  formation 
  of 
  the 
  major 
  glaciation, 
  

   viz., 
  clay 
  with 
  flints 
  and 
  upland 
  brickearth. 
  Map 
  3 
  (which 
  is 
  an 
  enlargement 
  

   of 
  the 
  corresponding 
  part 
  of 
  Map 
  2 
  in 
  the 
  greater 
  detail 
  which 
  the 
  larger 
  scale 
  

   of 
  it 
  allows, 
  with 
  the 
  gravels 
  c, 
  e, 
  and/ 
  shown 
  in 
  it 
  as 
  bedded 
  in 
  the 
  channels 
  

   around 
  the 
  islands) 
  should 
  be 
  compared 
  with 
  the 
  similar 
  portion 
  of 
  Map 
  4, 
  and 
  

   it 
  will 
  be 
  seen 
  that 
  the 
  Colne 
  channel 
  came 
  into 
  existence 
  by 
  the 
  coalescence 
  

   into 
  one 
  island 
  from 
  emergence 
  of 
  the 
  several 
  small 
  islands, 
  shown 
  in 
  Sheets 
  7, 
  

   46, 
  and 
  47 
  of 
  Map 
  4, 
  and 
  by 
  the 
  origin 
  from 
  emergence 
  of 
  the 
  islands 
  to 
  the 
  

   east 
  of 
  the 
  Channel, 
  in 
  Sheet 
  7. 
  The 
  ice 
  as 
  it 
  reached 
  this 
  more 
  lofty 
  (coalesced) 
  

   island 
  to 
  the 
  west 
  of 
  the 
  Channel, 
  was 
  checked 
  by 
  it, 
  so 
  that 
  after 
  over- 
  

   whelming 
  the 
  two 
  shown 
  in 
  Sheets 
  46 
  and 
  47 
  within 
  the 
  line 
  (and 
  which 
  are 
  

   enveloped 
  by 
  the 
  Chalky 
  Clay 
  to 
  their 
  highest 
  elevation, 
  which 
  is 
  550 
  feet 
  above 
  

   O.D.), 
  it 
  issued 
  through 
  this 
  Channel 
  in 
  the 
  way 
  shown 
  by 
  the 
  tongue-like 
  pro- 
  

   jection 
  of 
  the 
  broken 
  line 
  which 
  marks 
  the 
  limit 
  of 
  the 
  Chalky 
  Clay 
  there 
  in 
  Map 
  3. 
  

   Somewhat 
  earlier 
  in 
  the 
  emergence 
  it 
  had 
  issued 
  by 
  the 
  Channel 
  to 
  the 
  north 
  

   of 
  this 
  island, 
  which 
  is 
  shown 
  in 
  the 
  centre 
  of 
  Sheet 
  46 
  of 
  Map 
  2 
  (see 
  Plate 
  to 
  

   first 
  part 
  of 
  memoir) 
  as 
  extending 
  over 
  the 
  water-parting 
  between 
  the 
  Ivel, 
  

   the 
  Ouzell, 
  and 
  the 
  Thame 
  — 
  patches 
  of 
  Chalky 
  Clay 
  occurring 
  there 
  which 
  are 
  

   delineated 
  in 
  Map 
  1 
  ; 
  but 
  its 
  movement 
  in 
  this 
  direction 
  seems 
  to 
  have 
  been 
  

   arrested, 
  while 
  it 
  was 
  continued 
  over 
  the 
  partings 
  between 
  the 
  Ivel, 
  Lea, 
  and 
  

   Colne*. 
  It 
  is 
  at 
  the 
  extremity 
  of 
  this 
  line 
  in 
  the 
  Colne 
  Channel 
  at 
  Birkett 
  

   Wood, 
  and 
  at 
  about 
  250 
  feet 
  elevation, 
  that 
  the 
  Chalky 
  Clay 
  underlain 
  by 
  the 
  

   gravel 
  c, 
  is 
  also 
  overlain 
  by 
  the 
  gravel 
  e 
  ; 
  the 
  sea 
  on 
  the 
  retreat 
  of 
  the 
  ice 
  having 
  

   re-entered 
  the 
  Channel 
  thus 
  far 
  from 
  the 
  south-westward. 
  

  

  In 
  the 
  south-east 
  of 
  Sheet 
  47 
  of 
  Map 
  3 
  this 
  line 
  is 
  shown 
  as 
  projecting 
  tongue- 
  

   like 
  clown 
  the 
  Blackwater 
  Channel 
  between 
  the 
  islands 
  of 
  Danbury 
  and 
  Tiptree, 
  

   which, 
  being 
  covered 
  with 
  the 
  gravel 
  b\ 
  do 
  not 
  appear 
  in 
  Map 
  4, 
  but 
  are 
  shown 
  

   as 
  emerged 
  in 
  Map 
  3. 
  This 
  projection 
  is 
  made 
  in 
  order 
  to 
  include 
  the 
  patch 
  of 
  

  

  * 
  This 
  arrest 
  we 
  may 
  infer 
  was 
  caused 
  by 
  the 
  resistance 
  offered 
  by 
  the 
  greater 
  

   elevation 
  of 
  the 
  parting 
  between 
  the 
  Ivel 
  and 
  Ouzell, 
  which 
  is 
  nearly 
  400 
  feet, 
  

   while 
  that 
  of 
  the 
  parting 
  between 
  the 
  Ivel 
  and 
  Lea 
  by 
  way 
  of 
  the 
  Beane 
  (which 
  

   is 
  the 
  one 
  that 
  the 
  Chalky 
  Clay 
  follows) 
  is 
  about 
  300 
  only, 
  the 
  elevations 
  of 
  all 
  the 
  

   partings 
  by 
  which 
  the 
  clav 
  crosses 
  from 
  the 
  Lea 
  (Beane) 
  to 
  the 
  Colne 
  Channel, 
  

   and 
  which 
  are 
  all 
  included 
  within 
  the 
  lower 
  plain 
  of 
  Mr. 
  Hughes's 
  section, 
  

   p. 
  678, 
  being 
  under 
  that 
  also. 
  

  

  