﻿456 
  MR. 
  S. 
  S. 
  BTJCKMAN 
  OX 
  THE 
  

  

  to 
  trace 
  the 
  true 
  correlation 
  of 
  the 
  Midford 
  and 
  Yeovil 
  Sands 
  with 
  

   the 
  various 
  strata 
  in 
  the 
  Cotteswolds. 
  

  

  1st. 
  The 
  Midford 
  Sands 
  are 
  on 
  the 
  same 
  horizon 
  as 
  the 
  Dispansum- 
  

   beds, 
  and 
  perhaps 
  as 
  some 
  of 
  the 
  higher 
  divisions. 
  

  

  2nd. 
  The 
  Yeovil 
  Sands 
  are 
  above 
  the 
  Disj^ansum-heds, 
  are 
  on 
  the 
  

   horizon 
  of 
  the 
  Dumortieria-, 
  the 
  Moorei-, 
  and 
  part 
  of 
  the 
  Opalinum- 
  

   beds. 
  

  

  If 
  I 
  have 
  been 
  able 
  to 
  make 
  my 
  remarks 
  clear, 
  it 
  follows 
  that 
  the 
  

   sands 
  were 
  by 
  no 
  means 
  contemporaneous 
  in 
  the 
  various 
  districts. 
  

   The 
  same 
  horizon 
  which 
  in 
  the 
  Haresfield-Wotton 
  district 
  is 
  noted 
  

   for 
  its 
  sand 
  is 
  blue 
  clay 
  at 
  Ilminster. 
  What 
  is 
  sand 
  at 
  Burton 
  

   Bradstock 
  is 
  an 
  ironshot 
  limestone 
  in 
  Gloucestershire. 
  What 
  are 
  

   the 
  consequences 
  of 
  this 
  upon 
  our 
  nomenclature 
  ? 
  The 
  style 
  of 
  

   nomenclature 
  in 
  general 
  use 
  at 
  present 
  combines 
  the 
  Cotteswold 
  

   Sands 
  plus 
  the 
  Cephalopoda-bed, 
  the 
  Midford 
  Sands, 
  and 
  the 
  Yeovil 
  

   Sands 
  under 
  one 
  name 
  " 
  Midford 
  Sands," 
  and, 
  placing 
  them 
  as 
  the 
  

   next 
  stage 
  above 
  the 
  Upper 
  Lias, 
  includes 
  them 
  in 
  the 
  Inferior 
  

   Oolite 
  Series 
  *. 
  As 
  I 
  have 
  shown, 
  however, 
  the 
  Cotteswold 
  Sands 
  

   and 
  even 
  part 
  of 
  the 
  Cephalopoda-bed, 
  and 
  the 
  Midford 
  Sands 
  so 
  far 
  

   as 
  we 
  know 
  them, 
  are 
  absolutely 
  contemporaneous 
  with 
  the 
  Upper 
  

   Lias 
  of 
  Ilminster. 
  The 
  diagram 
  (fig. 
  1, 
  facing 
  this 
  page) 
  will 
  

   exhibit 
  this 
  at 
  a 
  glance. 
  

  

  I 
  may 
  note 
  the 
  following 
  facts 
  to 
  support 
  my 
  statement 
  that 
  the 
  

   Striatuhim-beds 
  are 
  in 
  the 
  Upper-Lias 
  Clay 
  of 
  Somerset— 
  that 
  the 
  

   top 
  of 
  this 
  clay 
  is, 
  in 
  fact, 
  on 
  the 
  same 
  horizon 
  as 
  the 
  Cotteswold 
  

   Sands 
  and 
  part 
  of 
  the 
  Cephalopoda-bed 
  of 
  Gloucestershire. 
  

  

  Charles 
  Moore, 
  who 
  always 
  considered 
  the 
  Yeovil 
  Sands 
  to 
  belong 
  

   to 
  the 
  Inferior 
  Oolite, 
  has 
  placed 
  the 
  following 
  species 
  in 
  the 
  Bath 
  

   Museum 
  as 
  from 
  the 
  Upper 
  Lias 
  of 
  Ilminster 
  f 
  : 
  — 
  

  

  Hammatoceras 
  insigne 
  (Schubler), 
  Grammoceras 
  striatuhtm 
  (Sow.), 
  

   Gramm. 
  fallaciosum, 
  Bayle, 
  Gramm., 
  sp. 
  (called 
  radians) 
  %. 
  

  

  Oppel, 
  ' 
  Juraformation,' 
  p. 
  250, 
  footnote, 
  says 
  "Mr. 
  Moore 
  aus 
  Bath 
  

   sandte 
  mir 
  den 
  Amm. 
  variabilis 
  aus 
  den 
  Umgebungen 
  von 
  Ilminster, 
  

   mit 
  dem 
  besondern 
  Bemerken, 
  dass 
  die 
  Exemplare 
  aus 
  dem 
  hochsten 
  

   Bette 
  des 
  obern 
  Lias 
  stammen. 
  Dies 
  ist 
  aber 
  nichts 
  anderes 
  als 
  die 
  

   zone 
  des 
  Amm. 
  jurensis." 
  

  

  With 
  these 
  facts 
  before 
  us 
  how 
  is 
  it 
  possible 
  to 
  treat 
  the 
  " 
  Midford 
  

   Sands" 
  as 
  of 
  later 
  date 
  than 
  the 
  "Upper 
  Lias," 
  seeing 
  that 
  the 
  

   greater 
  part 
  of 
  two 
  of 
  their 
  constituents 
  are 
  absolutely 
  contempo- 
  

   raneous 
  therewith 
  ? 
  

  

  * 
  H. 
  B. 
  Woodward, 
  ' 
  Geol. 
  England 
  and 
  Wales,' 
  2nd 
  ed. 
  p. 
  285 
  et 
  seq. 
  

  

  t 
  It 
  is 
  instructive 
  to 
  notice 
  how 
  Dr. 
  Wright 
  has 
  interpreted 
  this 
  fact 
  con- 
  

   cerning 
  the 
  Ilminster 
  strata, 
  and 
  brought 
  it 
  into 
  accordance 
  with 
  Gloucestershire. 
  

   In 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xii. 
  1856, 
  " 
  Upper 
  Lias 
  Sands,"' 
  p. 
  317, 
  he 
  states 
  

   that 
  in 
  three 
  horizons 
  which 
  he 
  calls, 
  beginning 
  with 
  the 
  lowest, 
  Upper 
  Lias 
  

   Clay, 
  Upper 
  Lias 
  Sands, 
  and 
  Upper 
  Lias 
  Cephalopoda-bed, 
  the 
  following 
  species 
  

   ot 
  Ammonites 
  have 
  been 
  found 
  — 
  Amm. 
  insignia, 
  Amm. 
  variabilis, 
  Amm. 
  radians, 
  

   Amm. 
  Baquinianus, 
  Amm. 
  concavus, 
  Amm. 
  striatulus. 
  Practically 
  speaking, 
  the 
  

   statement 
  is 
  true 
  enough 
  ; 
  but 
  they 
  are 
  not 
  three 
  horizons. 
  They 
  are 
  one 
  and 
  

   the 
  same 
  horizon 
  showing 
  a 
  lithology 
  varying 
  with 
  the 
  locality 
  ; 
  this 
  it 
  is 
  that 
  

   has 
  misled 
  him. 
  

  

  % 
  Compare 
  also 
  Moore, 
  Proc. 
  Somerset 
  Arch. 
  Soc. 
  vol. 
  xiii. 
  p. 
  131 
  (1865-66). 
  

  

  