﻿18G 
  W. 
  TOPLEV 
  ON 
  AREAS 
  OE 
  APPARENT 
  UPHEAVAL. 
  

  

  19. 
  On 
  the 
  Correspondence 
  between 
  some 
  Areas 
  of 
  Apparent 
  Up- 
  

   heaval 
  and 
  the 
  Thickening 
  of 
  Subjacent 
  Beds. 
  By 
  W. 
  Topley, 
  

   Esq., 
  F.G.S., 
  Geological 
  Survey 
  of 
  England 
  and 
  Wales. 
  (Bead 
  

   February 
  4, 
  1874.) 
  

  

  Contents. 
  

  

  1. 
  Introduction. 
  

  

  2. 
  The 
  Jurassic 
  and 
  Triassic 
  Rocks 
  of 
  Central 
  England. 
  

  

  3. 
  The 
  Oolitic 
  Rocks 
  of 
  Yorkshire. 
  

  

  4. 
  The 
  Carboniferous 
  Rocks 
  of 
  Yorkshire. 
  

  

  5. 
  The 
  Carboniferous 
  Rocks 
  of 
  Derbyshire. 
  

  

  6. 
  The 
  Weald. 
  

  

  7. 
  Observations 
  on 
  Basins. 
  

  

  8. 
  Conclusion. 
  

  

  1. 
  Introduction. 
  — 
  The 
  fact 
  that 
  the 
  Secondary 
  strata 
  of 
  England 
  

   vary 
  considerably 
  in 
  thickness 
  as 
  we 
  trace 
  them 
  over 
  any 
  wide 
  area 
  

   is 
  very 
  well 
  known. 
  Brofessor 
  Bhillips 
  long 
  ago 
  observed 
  the 
  south- 
  

   easterly 
  thinning 
  of 
  the 
  Oolites 
  in 
  the 
  Midland 
  Counties 
  * 
  ; 
  and 
  

   Brofessor 
  Hull, 
  in 
  1859, 
  read 
  before 
  this 
  Society 
  a 
  Memoir 
  on 
  this 
  

   subject, 
  giving 
  the 
  results 
  obtained 
  by 
  himself 
  and 
  others 
  engaged 
  

   on 
  the 
  Geological 
  Surveyf. 
  Becent 
  investigations 
  as 
  to 
  the 
  probable 
  

   extension 
  of 
  the 
  coal-measures 
  under 
  the 
  south-eastern 
  counties, 
  have 
  

   again 
  drawn 
  attention 
  to 
  this 
  subject 
  ; 
  and 
  much 
  information 
  bearing 
  

   upon 
  it 
  is 
  contained 
  in 
  the 
  Beports 
  of 
  the 
  Boyal 
  Coal 
  Commission. 
  

  

  In 
  the 
  following 
  paper 
  I 
  shall 
  endeavour 
  to 
  show 
  that, 
  from 
  these 
  

   facts, 
  some 
  important 
  conclusions 
  may 
  be 
  drawn 
  concerning 
  the 
  ob- 
  

   served 
  dip 
  of 
  the 
  strata, 
  and 
  the 
  disturbances 
  which 
  the 
  strata 
  are 
  as- 
  

   • 
  sumed 
  to 
  have 
  undergone, 
  conclusions 
  which 
  I 
  think 
  cannot 
  be 
  denied 
  

   if 
  the 
  facts 
  be 
  granted, 
  but 
  which 
  have 
  hitherto 
  been 
  overlooked. 
  

  

  It 
  is 
  known 
  that 
  the 
  Tertiary 
  and 
  Cretaceous 
  beds 
  under 
  London 
  

   lie 
  in 
  a 
  " 
  basin," 
  whilst 
  as 
  we 
  recede 
  from 
  London 
  the 
  beds 
  rise 
  at 
  

   varying 
  angles 
  ; 
  so 
  that 
  strata 
  which 
  occur 
  at 
  considerable 
  depths 
  

   under 
  London 
  attain 
  great 
  elevations 
  in 
  the 
  surrounding 
  districts. 
  

   It 
  has 
  always 
  been 
  assumed 
  that 
  this 
  is 
  due 
  to 
  an 
  upheaval 
  of 
  the 
  

   beds 
  in 
  the 
  direction 
  in 
  which 
  they 
  rise. 
  I 
  think, 
  however, 
  that 
  if 
  

   we 
  allow 
  the 
  full 
  weight 
  to 
  known 
  facts 
  as 
  to 
  the 
  thinning 
  out 
  of 
  

   beds 
  (facts 
  which 
  every 
  one 
  accepts), 
  we 
  must 
  conclude 
  that 
  this 
  is 
  

   in 
  many 
  cases 
  an 
  erroneous 
  assumption. 
  In 
  some 
  cases 
  the 
  observed 
  

   dip 
  and 
  rise 
  of 
  the 
  beds 
  can 
  be 
  wholly 
  accounted 
  for 
  by 
  the 
  known 
  

   or 
  inferred 
  thinning 
  and 
  thickening 
  of 
  the 
  beds. 
  

  

  Not, 
  however, 
  the 
  thinning 
  of 
  beds 
  the 
  dip 
  of 
  which 
  is 
  seen 
  ; 
  

   although 
  this 
  has 
  some 
  small 
  effect. 
  But 
  we 
  must 
  take 
  into 
  account 
  

   the 
  sum 
  of 
  the 
  thinning 
  of 
  all 
  the 
  underlying 
  beds. 
  If 
  we 
  do 
  this, 
  

   we 
  can 
  often 
  account, 
  not 
  for 
  a 
  part 
  only, 
  but 
  for 
  the 
  whole 
  of 
  the 
  

   observed 
  dip. 
  

  

  * 
  Manual 
  of 
  Geology, 
  p. 
  303. 
  

  

  t 
  " 
  On 
  the 
  South-easterly 
  Attenuation 
  of 
  the 
  Lower 
  Secondary 
  Formations 
  of 
  

   England," 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xvi. 
  p. 
  63. 
  

  

  