﻿COTTESWOLD, 
  MIDFOKD, 
  AND 
  YEOVIL 
  SANDS, 
  ETC. 
  457 
  

  

  On 
  the 
  other 
  hand 
  the 
  " 
  Midford 
  Sands 
  " 
  have 
  been 
  defined 
  as 
  

   equal 
  to 
  the 
  zones 
  of 
  Amm. 
  ojpalinus 
  and 
  Amm. 
  jurensis 
  * 
  ; 
  but, 
  

   in 
  all 
  probability, 
  the 
  lower 
  part 
  of 
  the 
  Cotteswold 
  Sands 
  — 
  the 
  part 
  

   containing 
  Amm. 
  bifrons 
  — 
  belongs 
  to 
  the 
  Commune-zone. 
  Then, 
  too, 
  

   it 
  is 
  just 
  the 
  opposite 
  in 
  Somerset, 
  where 
  it 
  is 
  the 
  Upper-Lias 
  Clay 
  

   of 
  Ilminster 
  which 
  contains 
  the 
  greater 
  part 
  of 
  the 
  Jurense-zone. 
  

   Again, 
  part 
  of 
  the 
  Inferior-Oolite 
  Limestone 
  of 
  Dorset 
  and 
  of 
  the 
  

   Cotteswolds 
  is 
  in 
  the 
  zone 
  of 
  Amm. 
  opalinus. 
  Therefore 
  this 
  latter 
  

   definition 
  does 
  not 
  coincide 
  with 
  the 
  first. 
  

  

  According 
  to 
  either 
  view 
  we 
  arrive 
  at 
  an 
  absurdity, 
  namely, 
  part 
  

   of 
  the 
  Upper-Lias 
  Clay 
  must 
  be 
  in 
  the 
  Inferior 
  Oolite 
  series 
  ; 
  or 
  

   beds 
  containing 
  several 
  of 
  the 
  same 
  species 
  of 
  Ammonites 
  must 
  be 
  

   in 
  the 
  Lias 
  in 
  one 
  place, 
  and 
  in 
  the 
  Inferior 
  Oolite 
  in 
  another. 
  

  

  After 
  all, 
  the 
  term 
  " 
  Midford 
  Sands 
  " 
  is 
  only 
  used 
  locally. 
  The 
  

   Dogger 
  Sands 
  of 
  Yorkshire, 
  and 
  part 
  of 
  the 
  Northampton 
  Sands, 
  

   are 
  contemporaneous 
  with 
  the 
  upper 
  part 
  of 
  the 
  Yeovil 
  Sands 
  ; 
  but 
  

   they 
  are 
  not 
  included 
  in 
  the 
  term 
  " 
  Midford 
  Sands." 
  Is 
  there 
  the 
  

   least 
  advantage 
  in 
  retaining 
  a 
  term 
  — 
  a 
  merely 
  local 
  term 
  — 
  which, 
  as 
  

   I 
  have 
  shown, 
  includes 
  deposits 
  that 
  are, 
  by 
  no 
  means, 
  contempor- 
  

   aneous? 
  Its 
  only 
  advantage 
  is 
  that 
  it 
  does 
  away 
  with 
  two 
  names; 
  

   but 
  the 
  result 
  is 
  absolute 
  inaccuracy. 
  The 
  terms 
  Cotteswold, 
  Mid- 
  

   ford, 
  and 
  Yeovil 
  Sands 
  may 
  be 
  retained 
  as 
  merely 
  local 
  names 
  for 
  

   certain 
  deposits, 
  in 
  the 
  same 
  way 
  as 
  Pea-grit, 
  Oolite 
  Marl, 
  &c. 
  ; 
  

   they 
  should 
  have 
  no 
  wider 
  signification 
  than 
  the 
  district 
  to 
  which 
  

   they 
  apply, 
  and 
  should 
  not 
  be 
  used 
  where 
  strict 
  scientific 
  accuracy 
  

   is 
  required, 
  but 
  should 
  give 
  place 
  to 
  their 
  zonal 
  equivalents. 
  

  

  It 
  would 
  almost 
  seem 
  as 
  if 
  the 
  sands 
  between 
  Liassic 
  Clay 
  and 
  

   Oolitic 
  Limestone 
  were 
  a 
  somewhat 
  singular 
  deposit 
  ; 
  but 
  the 
  fact 
  

   of 
  the 
  matter 
  is, 
  that 
  from 
  a 
  rather 
  remote 
  period 
  until 
  a 
  much 
  

   later 
  one 
  than 
  we 
  are 
  treating 
  of, 
  sandy 
  strata 
  have 
  been 
  deposited 
  — 
  

   in 
  no 
  two 
  districts 
  contemporaneously, 
  but 
  generally 
  first 
  in 
  one 
  

   place 
  and 
  then 
  in 
  another. 
  Why, 
  then, 
  is 
  it 
  desired 
  to 
  mark 
  off 
  the 
  

   " 
  Midford 
  Sands 
  " 
  as 
  a 
  distinct 
  series 
  — 
  not 
  all 
  across 
  England, 
  but 
  

   only 
  locally 
  ? 
  

  

  The 
  Jamesoni- 
  and 
  Caprleornum- 
  zones 
  are 
  characterized 
  by 
  mica- 
  

   ceous 
  and 
  sandy 
  shales 
  at 
  Eobin 
  Hood's 
  Bay 
  in 
  Yorkshire 
  t. 
  

  

  The 
  Henley 
  i-zone 
  in 
  Gloucestershire 
  is 
  largely 
  made 
  up 
  of 
  sandy 
  

   strata 
  very 
  similar 
  to 
  the 
  Cotteswold 
  Sands. 
  

  

  The 
  Margaritatus- 
  and 
  Spinatus-zones 
  in 
  Dorset 
  contain 
  sandy 
  

   strata 
  often 
  undistingnishable 
  from 
  the 
  Yeovil 
  Sands. 
  

  

  The 
  zone 
  of 
  Amm. 
  annulatus 
  in 
  Yorkshire 
  is 
  represented 
  by 
  hard 
  

   and 
  compact, 
  grey 
  and 
  micaceous 
  sandy 
  shale 
  t. 
  

  

  What 
  is 
  probably 
  the 
  upper 
  part 
  of 
  the 
  Commune-zone 
  is 
  com- 
  

   posed 
  of 
  micaceous 
  sands 
  in 
  Gloucestershire. 
  

  

  The 
  Jurense-zone 
  is 
  made 
  up 
  of 
  sands 
  at 
  Bath, 
  while, 
  lastly, 
  the 
  

   OpaUnum-zone 
  at 
  Burton 
  Bradstock 
  is 
  chiefly 
  sands. 
  

  

  Passing 
  to 
  the 
  continent, 
  Oppel 
  § 
  shows 
  us 
  that 
  at 
  Wasseralfingen 
  

  

  * 
  H. 
  B. 
  Woodward, 
  op. 
  cit. 
  p. 
  285. 
  

   f 
  H. 
  B. 
  Woodward, 
  op. 
  cit. 
  p. 
  269. 
  

   | 
  H. 
  B. 
  Woodward, 
  op. 
  fit. 
  p. 
  277. 
  

   § 
  Oppel. 
  ' 
  Juraformation.' 
  p. 
  328. 
  

  

  