﻿W. 
  TOPLET 
  OK 
  AREAS 
  OF 
  APPARENT 
  UPHEAVAL. 
  189 
  

  

  these 
  rocks 
  would 
  he 
  affected 
  by 
  this 
  amount, 
  besides 
  that 
  resulting 
  

   from 
  the 
  thinning 
  of 
  the 
  higher 
  Secondary 
  rocks 
  themselves. 
  

  

  We 
  see, 
  then, 
  that 
  in 
  estimating 
  the 
  dip 
  of 
  the 
  beds 
  in 
  any 
  such 
  

   district, 
  our 
  results 
  will 
  vary 
  according 
  to 
  the 
  rocks 
  which 
  are 
  exposed 
  

   in 
  it. 
  But 
  inasmuch 
  as 
  our 
  knowledge 
  of 
  the 
  great 
  movements 
  which 
  

   have 
  affected 
  the 
  earth's 
  crust 
  is 
  generally 
  deduced 
  from 
  such 
  obser- 
  

   vations, 
  this 
  liability 
  to 
  error 
  becomes 
  a 
  very 
  serious 
  matter. 
  

  

  We 
  infer, 
  for 
  instance, 
  because 
  of 
  what 
  we 
  know 
  of 
  the 
  dip 
  

   of 
  the 
  Great 
  Oolite 
  in 
  Gloucestershire 
  and 
  Oxfordshire, 
  that 
  the 
  

   beds 
  have 
  been 
  upheaved 
  towards 
  the 
  west 
  and 
  north-west, 
  which 
  

   has 
  resulted 
  in 
  a 
  dip 
  to 
  the 
  east 
  and 
  south-east, 
  or 
  towards 
  the 
  

   London 
  basin. 
  But 
  if, 
  over 
  this 
  area, 
  denudation 
  had 
  gone 
  much 
  

   further 
  than 
  it 
  has 
  done, 
  and 
  all 
  the 
  Oolites 
  down 
  to 
  the 
  higher 
  part 
  

   of 
  the 
  Lower 
  Lias 
  had 
  been 
  swept 
  away, 
  w 
  r 
  e 
  should 
  observe 
  that 
  the 
  

   beds 
  along 
  this 
  line 
  were 
  approximately 
  flat 
  ; 
  and 
  we 
  should 
  infer 
  

   that 
  there 
  had 
  been 
  no 
  upheaval 
  here, 
  or 
  that 
  the 
  net 
  results 
  of 
  

   such 
  movements 
  as 
  had 
  taken 
  place 
  had 
  been 
  to 
  leave 
  the 
  beds 
  in 
  a 
  

   horizontal 
  position. 
  If 
  the 
  whole 
  of 
  the 
  Lias 
  had 
  been 
  denuded, 
  we 
  

   should 
  infer 
  a 
  slight 
  westerly 
  dip 
  or 
  from 
  the 
  London 
  basin. 
  If 
  

   denudation 
  had 
  gone 
  far 
  into 
  the 
  Trias, 
  sweeping 
  away 
  the 
  whole 
  

   of 
  the 
  higher 
  Secondary 
  rocks, 
  we 
  might 
  have 
  inferred 
  a 
  considerable 
  

   westerly 
  dip 
  *. 
  

  

  3. 
  The 
  Oolitic 
  RocJcs 
  of 
  Yorkshire. 
  — 
  These 
  afford 
  another 
  very 
  

   striking 
  example. 
  It 
  is 
  known 
  that 
  the 
  entire 
  Oolitic 
  series, 
  which 
  

   is 
  so 
  magnificently 
  developed 
  in 
  the 
  northern 
  part 
  of 
  the 
  county, 
  is 
  

   absent 
  under 
  the 
  Wolds, 
  and 
  that 
  the 
  Bed 
  Chalk 
  there 
  rests 
  directly 
  

   on 
  the 
  Lower 
  Lias. 
  In 
  part, 
  no 
  doubt, 
  this 
  is 
  due 
  to 
  the 
  great 
  un- 
  

   conformity 
  between 
  the 
  Cretaceous 
  and 
  Oolitic 
  rocks 
  ; 
  but 
  it 
  is 
  also 
  

   partly 
  due 
  to 
  actual 
  thinning 
  of 
  the 
  strata, 
  the 
  Lower 
  Oolites 
  having 
  

   disappeared 
  entirely 
  in 
  this 
  manner. 
  

  

  In 
  order 
  to 
  estimate 
  the 
  amount 
  of 
  the 
  dip 
  which 
  is 
  due 
  to 
  this 
  

   thinning, 
  we 
  have 
  only 
  to 
  compare 
  the 
  small 
  actual 
  southerly 
  fall 
  

   of 
  the 
  bottom 
  of 
  the 
  Inferior 
  Oolite 
  along 
  the 
  base 
  of 
  the 
  western 
  

   escarpment 
  with 
  the 
  great 
  southerly 
  dip 
  which 
  the 
  Coral 
  Crag 
  would 
  

   have 
  if 
  it 
  now 
  stretched 
  (as 
  once 
  it 
  did) 
  along 
  the 
  top 
  of 
  that 
  escarp- 
  

   ment. 
  But 
  this 
  is 
  not 
  all 
  ; 
  for 
  the 
  Lias 
  itself 
  is 
  thinning 
  in 
  the 
  same 
  

   manner, 
  and 
  we 
  find 
  that 
  the 
  base 
  of 
  the 
  Lias 
  undergoes 
  comparatively 
  

   small 
  changes 
  of 
  level 
  along 
  the 
  same 
  north 
  and 
  south 
  line. 
  

  

  4. 
  The 
  Carboniferous 
  Mocks 
  of 
  Yorkshire. 
  — 
  The 
  Carboniferous 
  

   Limestone 
  series 
  of 
  Yorkshire 
  has 
  a 
  general 
  dip, 
  from 
  the 
  high 
  land 
  of 
  

  

  * 
  Since 
  this 
  paper 
  was 
  read, 
  Mr. 
  Whitaker 
  has 
  kindly 
  drawn 
  my 
  attention 
  f 
  o 
  

   the 
  following 
  remarks 
  by 
  Sir 
  W. 
  V. 
  Guise, 
  in 
  his 
  address 
  to 
  the 
  Cotteswold 
  

   Naturalists' 
  Field 
  Club, 
  April 
  10, 
  1869. 
  Referring 
  to 
  the 
  meeting 
  of 
  the 
  Club 
  

   held 
  on 
  March 
  25, 
  18GS, 
  Sir 
  W. 
  Guise 
  says 
  : 
  — 
  " 
  Mr. 
  Lucy 
  mentioned 
  bis 
  having 
  

   recently 
  made 
  an 
  excursion 
  in 
  the 
  Cotleswolds 
  round 
  Stow 
  and 
  Burford, 
  and 
  

   called 
  attention 
  to 
  the 
  gradual 
  thinning 
  out 
  of 
  the 
  beds 
  in 
  a 
  northerly 
  [?} 
  

   direction. 
  On 
  the 
  authority 
  of 
  Mr. 
  Hull's 
  Memoirs, 
  to 
  illustrate 
  Map 
  44, 
  

   Geological 
  Survey, 
  he 
  stated 
  that, 
  while 
  at 
  Cleeve 
  Cloud 
  the 
  Inferior 
  Oolite 
  

   attains 
  an 
  elevation 
  of 
  1130 
  feet, 
  the 
  Cornbrash 
  south 
  of 
  Burford 
  is 
  not 
  much 
  

   more 
  than 
  one 
  half 
  that 
  height. 
  This, 
  however, 
  is 
  in 
  some 
  degree 
  due 
  to 
  the 
  

   greatly 
  diminished, 
  thickness 
  of 
  the 
  underlying, 
  strata 
  in 
  the 
  latter 
  locality" 
  

  

  Q.'J. 
  G. 
  B. 
  No. 
  118. 
  p 
  

  

  