﻿710 
  

  

  SEARLES 
  V. 
  WOOD 
  ON 
  THE 
  NEWER 
  

  

  turbance 
  since 
  that 
  formation, 
  by 
  which, 
  it 
  seems 
  to 
  me, 
  the 
  denu- 
  

   dation 
  was 
  induced 
  which 
  has 
  removed 
  the 
  greater 
  part 
  of 
  it 
  there 
  : 
  

   and 
  in 
  order 
  to 
  enable 
  this 
  to 
  be 
  seen, 
  I 
  have 
  given 
  the 
  many 
  lines 
  

   of 
  section 
  across 
  this 
  part 
  of 
  the 
  valley 
  which 
  are 
  contained 
  in 
  Plate 
  

   XXVI. 
  A 
  consideration 
  of 
  all 
  the 
  features 
  thus 
  disclosed 
  will, 
  I 
  think, 
  

   show 
  also 
  that 
  this 
  disturbance 
  with 
  its 
  resulting 
  denudation 
  was 
  

   renewed 
  after 
  the 
  accumulation 
  of 
  the 
  gravel 
  g. 
  Such 
  disturbance 
  

   with 
  denudation 
  of 
  the 
  bottom 
  seems 
  to 
  be 
  the 
  usual 
  accompani- 
  

   ment 
  of 
  any 
  general 
  movement 
  of 
  upheaval 
  ; 
  for 
  in 
  the 
  case 
  of 
  that 
  

   great 
  one 
  which 
  took 
  place 
  during 
  the 
  major 
  glaciation, 
  it 
  gave 
  

   rise 
  to 
  the 
  rectilinear 
  upturn 
  of 
  the 
  Hogsback, 
  which 
  placed 
  the 
  

   gravel 
  V 
  in 
  the 
  position 
  shown 
  in 
  fig. 
  II., 
  and 
  to 
  that 
  of 
  the 
  Isles 
  

   of 
  Wight 
  and 
  Purbeck, 
  which 
  placed 
  the 
  same 
  gravel 
  in 
  the 
  posi- 
  

   tion 
  shown 
  in 
  fig. 
  IV. 
  * 
  ; 
  while 
  in 
  the 
  case 
  of 
  that 
  minor 
  one 
  which 
  

   took 
  place 
  during 
  the 
  Cyrena 
  -formation, 
  and 
  the 
  minor 
  glaciation 
  

   which 
  followed 
  this, 
  it 
  gave 
  rise 
  to 
  the 
  disturbances 
  I 
  am 
  about 
  to 
  

   trace. 
  

  

  In 
  Sheet 
  1 
  (see 
  Map 
  3) 
  there 
  is 
  on 
  the 
  south 
  side 
  of 
  the 
  Thames, 
  

   between 
  Greenwich 
  and 
  Erith, 
  neither 
  gravel 
  nor 
  brickearth 
  of 
  any 
  

   Jcind 
  above 
  the 
  marsh 
  alluvium, 
  except 
  the 
  isolated 
  patch 
  of 
  the 
  

   Cyrena-brickesiTth. 
  in 
  "Wickham 
  Lane 
  shown 
  in 
  fig. 
  XXXIII., 
  and 
  the 
  

   trace 
  of 
  this 
  on 
  the 
  chalk 
  in 
  fig. 
  XXXIV. 
  ; 
  while 
  both 
  to 
  the 
  east 
  and 
  

   west 
  of 
  those 
  places 
  gravel 
  rises 
  to 
  elevations 
  exceeding 
  100 
  feet 
  

   (see 
  figs. 
  XXXVII. 
  and 
  XXXVIIL, 
  and 
  figs. 
  XXI. 
  and 
  XXII.). 
  

   Between 
  Greenwich 
  and 
  Erith, 
  where 
  the 
  beds 
  /, 
  <p, 
  and 
  g 
  are 
  thus 
  

   absent 
  above 
  the 
  marsh, 
  the 
  Lower 
  Tertiaries 
  below 
  it 
  are 
  known 
  

   to 
  be 
  faulted 
  t 
  ; 
  and 
  this 
  is 
  probably 
  the 
  case 
  also 
  between 
  Crossness 
  

   and 
  Wickham 
  Lane 
  in 
  fig. 
  XXXIII. 
  The 
  connexion 
  of 
  the 
  gravel 
  

   with 
  these 
  faults 
  is 
  concealed 
  by 
  the 
  peat 
  and 
  marsh 
  clay, 
  except 
  at 
  

   Charlton 
  ; 
  and 
  there 
  the 
  disturbance 
  connected 
  with 
  these 
  faults 
  

   brings 
  up 
  the 
  chalk 
  bare 
  of 
  gravel, 
  not 
  only 
  on 
  the 
  .south 
  side 
  of 
  the 
  

   river, 
  but 
  in 
  the 
  south 
  side 
  of 
  its 
  bed, 
  though 
  the 
  northern 
  half 
  of 
  

   the 
  river-bed 
  here, 
  like 
  the 
  northern 
  shore, 
  is 
  gravel-covered. 
  Over 
  

   the 
  whole 
  northern 
  side 
  of 
  the 
  valley 
  corresponding 
  to 
  this 
  deficient 
  

   southern 
  part, 
  the 
  gravels 
  g 
  and 
  / 
  (and 
  so 
  much 
  of 
  the 
  Cyrena-for- 
  

   mation, 
  </>, 
  as 
  may 
  be 
  left 
  there) 
  spread 
  in 
  a 
  continuous 
  sheet 
  up 
  

   to 
  the 
  elevation 
  of 
  100 
  feet 
  and 
  more 
  (see 
  figs. 
  XXXIII. 
  and 
  

   XXXVIIL), 
  and 
  no 
  terrace, 
  save 
  such 
  as 
  g 
  and 
  <p 
  make 
  in 
  fig. 
  

   XXXVIIL, 
  can 
  be 
  detected. 
  East 
  of 
  this, 
  in 
  the 
  part 
  crossed 
  by 
  

   the 
  lines 
  of 
  figs. 
  VI. 
  (see 
  plate 
  to 
  first 
  part 
  of 
  this 
  memoir), 
  XXL, 
  

   and 
  XXIL, 
  <p 
  lies 
  in 
  a 
  well-defined 
  terrace 
  below 
  /, 
  with 
  g 
  in 
  a 
  

   terrace 
  below 
  and 
  up 
  to 
  <p 
  ; 
  but 
  more 
  frequently 
  is 
  absent, 
  and 
  its 
  

   place 
  occupied 
  by 
  g 
  lying 
  (up 
  to 
  the 
  level 
  of 
  from 
  25 
  to 
  30 
  feet 
  above 
  

   O. 
  D., 
  which 
  it 
  reaches 
  here) 
  in 
  a 
  terrace 
  below/, 
  as 
  shown 
  at 
  the 
  

  

  * 
  Also 
  to 
  that 
  continuation 
  of 
  the 
  Wight 
  and 
  Purbeck 
  upturn 
  which 
  is 
  

   shown 
  inProf. 
  Prestwich's 
  Weymouth 
  section 
  (Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxxi.), 
  

   where 
  the 
  gravel 
  on 
  the 
  Tertiary 
  over 
  the 
  chalk 
  is 
  shown 
  cut 
  off 
  at 
  this 
  upturn, 
  

   as 
  it 
  is 
  in 
  my 
  figs. 
  II. 
  to 
  V. 
  

  

  t 
  De 
  la 
  Condaniine, 
  in 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  vi. 
  p. 
  441, 
  and 
  vol. 
  viii. 
  

   p. 
  193. 
  

  

  