﻿W. 
  T0P1EY 
  ON 
  AREAS 
  OP 
  APPARENT 
  UPHEAVAL. 
  191 
  

  

  The 
  rise 
  of 
  the 
  Cretaceous 
  beds 
  towards 
  the 
  central 
  anticlinal 
  of 
  

   the 
  "Weald 
  is 
  too 
  well 
  known 
  to 
  need 
  description 
  here. 
  The 
  base 
  of 
  

   the 
  Ganlt, 
  which 
  is 
  940 
  feet 
  below 
  sea-level 
  at 
  the 
  Kentish-Town 
  

   well, 
  would 
  be 
  rather 
  more 
  than 
  2000 
  feet 
  above 
  the 
  sea, 
  if 
  the 
  

   Lower 
  Cretaceous 
  beds 
  were 
  restored 
  over 
  Crowborough 
  Beacon, 
  

   the 
  highest 
  point 
  along 
  the 
  central 
  anticlinal 
  of 
  the 
  Weald. 
  "We 
  

   may 
  therefore 
  take 
  3000 
  feet 
  as 
  the 
  difference 
  of 
  level 
  of 
  the 
  base 
  

   of 
  the 
  Gault 
  between 
  the 
  centre 
  of 
  the 
  Weald 
  and 
  Kentish 
  Town. 
  

   For 
  the 
  present 
  we 
  will 
  leave 
  out 
  of 
  consideration 
  the 
  minor 
  anti- 
  

   clinals 
  of 
  the 
  Weald, 
  and 
  will 
  speak 
  only 
  of 
  the 
  great 
  and 
  general 
  

   anticlinal. 
  

  

  At 
  Kentish 
  Town 
  the 
  Gault 
  rests 
  almost 
  directly 
  upon 
  Palaeozoic 
  

   rocks* 
  ; 
  at 
  Crowborough 
  there 
  would 
  be 
  at 
  least 
  2000 
  feet 
  of 
  strata 
  

   between 
  them. 
  How 
  much 
  more 
  than 
  this 
  there 
  may 
  be 
  we 
  shall 
  

   shortly 
  know 
  by 
  the 
  sub-Wealden 
  boring. 
  But 
  supposing, 
  in 
  order 
  

   to 
  simplify 
  the 
  subject, 
  that 
  the 
  Palaeozoic 
  rocks 
  are 
  met 
  with 
  at 
  a 
  

   depth 
  of 
  940 
  feet 
  below 
  the 
  sea, 
  then 
  is 
  it 
  not 
  plain 
  that 
  the 
  actual 
  

   rise 
  of 
  the 
  Gault 
  towards 
  the 
  centre 
  of 
  the 
  Weald 
  is 
  accounted 
  for 
  

   by 
  the 
  gradual 
  thickening 
  of 
  the 
  underlying 
  beds 
  ? 
  The 
  palaeozoic 
  

   floor 
  would 
  be 
  a 
  horizontal 
  line 
  (disregarding 
  still 
  the 
  minor 
  folds) 
  ; 
  

   the 
  Oolitic, 
  Wealden, 
  and 
  Neocomian 
  strata 
  would 
  all 
  dip 
  to 
  the 
  

   north, 
  the 
  higher 
  beds 
  dipping 
  more 
  rapidly 
  than 
  the 
  lower 
  ; 
  the 
  

   Gault 
  would 
  have 
  the 
  maximum 
  dip 
  of 
  3000 
  feet 
  in 
  36 
  miles. 
  

  

  If 
  it 
  be 
  true 
  that 
  great 
  movements 
  which 
  have 
  affected 
  the 
  strata 
  

   near 
  the 
  surface 
  have 
  had 
  an 
  equal 
  influence 
  on 
  those 
  below 
  (and 
  upon 
  

   this 
  assumption 
  a 
  large 
  portion 
  of 
  our 
  geological 
  theories 
  are 
  based), 
  

   then 
  the 
  converse 
  of 
  this 
  should 
  be 
  equally 
  true 
  : 
  — 
  If 
  in 
  any 
  area 
  we 
  

   can 
  show 
  that 
  deeply 
  buried 
  strata 
  are 
  undisturbed, 
  should 
  we 
  not 
  

   infer 
  that 
  no 
  great 
  disturbance 
  has 
  affected 
  the 
  overlying 
  rocks, 
  and 
  

   that 
  the 
  dip 
  of 
  these 
  higher 
  beds 
  must 
  be 
  due 
  to 
  some 
  other 
  cause 
  ? 
  

  

  But 
  since 
  the 
  beds 
  with 
  which 
  we 
  are 
  now 
  dealing 
  are 
  partly 
  of 
  

   freshwater 
  origin, 
  we 
  cannot 
  apply 
  the 
  same 
  reasoning 
  to 
  them 
  as 
  

   we 
  can 
  to 
  those 
  which 
  are 
  wholly 
  marine. 
  The 
  thinning 
  of 
  the 
  

   Jurassic 
  rocks 
  may 
  be 
  due 
  to 
  failure 
  of 
  sediment 
  in 
  a 
  south-easterly 
  

   direction, 
  where 
  was 
  probably 
  the 
  open 
  sea 
  ; 
  this 
  is 
  rendered 
  likely 
  

   by 
  the 
  fact 
  that 
  the 
  limestone 
  beds 
  of 
  the 
  Great 
  Oolite 
  do 
  not, 
  so 
  far 
  

   as 
  they 
  can 
  be 
  observed, 
  thin 
  in 
  that 
  direction. 
  If 
  the 
  Wealden 
  rocks 
  

   were 
  deposited 
  in 
  a 
  delta, 
  the 
  direction 
  in 
  which 
  the 
  freshwater 
  

   sediment 
  failed 
  would 
  also 
  be 
  that 
  in 
  which 
  marine 
  conditions 
  most 
  

   prevailed. 
  But, 
  so 
  far 
  as 
  we 
  know, 
  marine 
  or 
  estuarine 
  forms 
  are, 
  

   in 
  the 
  English 
  Wealden 
  beds, 
  confined 
  to 
  the 
  highest 
  and 
  lowest 
  

   members 
  of 
  that 
  series, 
  and 
  where 
  the 
  beds 
  are 
  seen 
  to 
  thin 
  out 
  

   against 
  the 
  old 
  rocks 
  they 
  are 
  still 
  of 
  freshwater 
  origin. 
  

  

  This 
  thinning 
  out, 
  however, 
  may 
  have 
  been 
  against 
  the 
  old 
  shore- 
  

   line 
  of 
  the 
  estuary 
  or 
  lake 
  ; 
  and 
  in 
  that 
  case 
  the 
  supposed 
  horizontal 
  

   position 
  of 
  the 
  palaeozoic 
  floor 
  would 
  probably 
  be 
  due 
  to 
  an 
  upheaval 
  

   of 
  the 
  bed 
  of 
  the 
  lake 
  or 
  delta, 
  or 
  to 
  a 
  sinking 
  of 
  the 
  old 
  land. 
  This 
  

   necessarily 
  complicates 
  the 
  question, 
  so 
  far 
  as 
  the 
  Weald 
  is 
  concerned 
  ; 
  

  

  * 
  There 
  has 
  been 
  doubt 
  as 
  to 
  the 
  age 
  of 
  the 
  lowest 
  rocks 
  found 
  in 
  this 
  well 
  ; 
  

   but 
  Mr. 
  Prestwich 
  now 
  regards 
  them 
  as 
  Old 
  Red 
  Sandstone. 
  

  

  p2 
  

  

  