﻿AV. 
  T0PLEY 
  OX 
  AREAS 
  OE 
  APPARENT 
  UPHEAVAL. 
  193 
  

  

  7. 
  Observations 
  on 
  Basins. 
  — 
  We 
  have 
  seen 
  that 
  there 
  is 
  a 
  very 
  

   general 
  tendency 
  for 
  beds 
  to 
  thin 
  towards 
  the 
  dip, 
  and 
  to 
  thicken 
  

   towards 
  the 
  rise 
  ; 
  but 
  the 
  illustrations 
  given 
  are 
  of 
  strata 
  which 
  

   support 
  geological 
  basins. 
  With 
  the 
  strata 
  forming 
  the 
  basins 
  

   themselves 
  the 
  reverse 
  appears 
  to 
  be 
  often 
  the 
  case 
  ; 
  they 
  thicken 
  

   towards 
  the 
  centre 
  of 
  the 
  basin. 
  

  

  This 
  is 
  certainly 
  the 
  case 
  with 
  the 
  Lower 
  Tertiary 
  strata 
  of 
  the 
  

   Loudon 
  basin 
  ; 
  it 
  seems 
  to 
  be 
  also 
  the 
  case 
  with 
  the 
  Hampshire 
  

   basin. 
  Professor 
  Hebert 
  informs 
  me 
  that 
  the 
  same 
  thing 
  occurs 
  in 
  

   the 
  Paris 
  basin 
  ; 
  whilst 
  the 
  Lower 
  Cretaceous 
  beds 
  which 
  support 
  

   that 
  basin 
  thicken 
  as 
  they 
  rise 
  to 
  the 
  west. 
  

  

  It 
  is 
  a 
  point 
  of 
  common 
  knowledge 
  amongst 
  the 
  mining 
  engineers 
  

   in 
  the 
  north 
  of 
  England 
  that 
  the 
  strata 
  of 
  the 
  Newcastle 
  coal- 
  

   field 
  thicken 
  towards 
  the 
  centre 
  of 
  the 
  basin. 
  The 
  seams 
  of 
  coal 
  

   are 
  at 
  a 
  greater 
  distance 
  apart 
  along 
  the 
  centre 
  of 
  the 
  basin 
  than 
  

   towards 
  its 
  western 
  margin, 
  the 
  easterly 
  dip 
  being 
  somewhat 
  greater 
  

   in 
  the 
  lower 
  seams 
  than 
  in 
  the 
  higher. 
  The 
  difference 
  of 
  the 
  dip 
  

   due 
  to 
  the 
  general 
  easterly 
  thickening 
  is 
  of 
  course 
  usually 
  small 
  ; 
  

   but 
  it 
  occasionally 
  happens 
  that 
  the 
  difference 
  is 
  very 
  marked, 
  and 
  

   in 
  consulting 
  colliery 
  plans 
  it 
  is 
  necessary 
  always 
  to 
  bear 
  in 
  mind 
  to 
  

   which 
  seam 
  the 
  plans 
  refer. 
  

  

  Besides 
  the 
  general 
  easterly 
  thickening 
  of 
  the 
  strata, 
  there 
  are 
  

   occasionally 
  local 
  thickenings 
  of 
  certain 
  parts, 
  the 
  result 
  of 
  which 
  is 
  

   to 
  cause 
  undulations 
  in 
  the 
  overlying 
  beds 
  which 
  are 
  apparently 
  the 
  

   result 
  of 
  movements 
  of 
  the 
  strata. 
  I 
  may 
  just 
  mention 
  one 
  case, 
  

   although 
  (as 
  the 
  area 
  in 
  question 
  is 
  not 
  yet 
  published 
  by 
  the 
  Geological 
  

   Survey) 
  I 
  cannot 
  give 
  full 
  details, 
  which, 
  indeed, 
  are 
  not 
  necessary. 
  

   An 
  important 
  scam 
  of 
  coal 
  on 
  the 
  north-east 
  of 
  Morpeth 
  had 
  been 
  

   worked 
  at 
  Ashington 
  to 
  its 
  regular 
  outcrop 
  on 
  the 
  west 
  ; 
  borings 
  

   carried 
  through 
  the 
  Boulder 
  Clay 
  still 
  further 
  west 
  proved 
  that 
  

   this 
  seam 
  rolled 
  in 
  again 
  in 
  a 
  small 
  basin, 
  in 
  which 
  a 
  large 
  colliery 
  

   (Longhirst) 
  is 
  now 
  working. 
  A 
  deep 
  bore-hole 
  put 
  down 
  at 
  the 
  

   outcrop 
  of 
  the 
  Ashington 
  seam 
  proves 
  that 
  some 
  sandstones 
  which 
  

   underlie 
  it 
  are 
  of 
  great 
  and 
  unusual 
  thickness 
  there 
  ; 
  from 
  this 
  we 
  

   may 
  infer 
  that 
  the 
  " 
  anticlinal," 
  which 
  throws 
  out 
  the 
  upper 
  seam 
  

   for 
  a 
  short 
  distance, 
  is 
  due, 
  largely 
  if 
  not 
  entirely, 
  to 
  the 
  local 
  

   thickening 
  of 
  this 
  sandstone. 
  Yet 
  if 
  these 
  were 
  rocks 
  which 
  were 
  

   not 
  deeply 
  explored 
  for 
  mining-purposes, 
  and 
  if 
  we 
  reasoned 
  only 
  

   by 
  what 
  we 
  see 
  at 
  the 
  surface, 
  we 
  should 
  certainly 
  refer 
  the 
  anti- 
  

   clinal 
  and 
  synclinal 
  in 
  question 
  only 
  to 
  movements 
  of 
  the 
  strata. 
  

  

  S. 
  Conclusion. 
  — 
  Whatever 
  value 
  may 
  be 
  attached 
  to 
  many 
  of 
  the 
  

   foregoing 
  remarks, 
  I 
  think 
  this 
  much 
  is 
  certain 
  : 
  enough 
  has 
  been 
  

   said 
  to 
  prove 
  that 
  great 
  caution 
  is 
  necessary 
  in 
  reasoning, 
  from 
  the 
  

   observed 
  dip 
  of 
  beds, 
  to 
  any 
  conclusions 
  as 
  to 
  great 
  movements 
  of 
  

   the 
  earth's 
  crust. 
  In 
  fact, 
  it 
  would 
  seem 
  that 
  we 
  can 
  never 
  feel 
  

  

  nard's 
  to 
  Bexhill, 
  are 
  of 
  considerable 
  interest, 
  as 
  they 
  appear 
  to 
  lose 
  much 
  of 
  

   their 
  thickness 
  before 
  they 
  pass 
  under 
  the 
  highest 
  part 
  of 
  the 
  Hastings 
  Sand 
  series 
  

   and 
  the 
  overlying 
  Weald 
  Clay 
  of 
  Povensey." 
  -Quart. 
  Journ. 
  Gcol. 
  Eoc. 
  vol. 
  xviii. 
  

   p. 
  252, 
  1862. 
  

  

  