﻿590 
  ME. 
  G. 
  W. 
  LAMPLTJGH 
  01ST 
  THE 
  

  

  While 
  my 
  own 
  researches 
  fail 
  to 
  reveal 
  any 
  break 
  in 
  the 
  strata 
  

   at 
  this 
  horizon, 
  which 
  I 
  regard 
  rather 
  as 
  a 
  passage-bed 
  in 
  which 
  

   the 
  two 
  faunas 
  meet, 
  wherein 
  there 
  is 
  necessarily 
  a 
  mingling 
  of 
  

   types, 
  as 
  shown 
  by 
  the 
  occurrence 
  of 
  Bel. 
  lateralis 
  smdAmm. 
  noricus 
  

   in 
  the 
  same 
  nodules, 
  they 
  are 
  yet 
  distinctly 
  favourable 
  to 
  Leckenby's 
  

   view 
  that 
  the 
  clays 
  up 
  to 
  this 
  point 
  may 
  be 
  included 
  with 
  the 
  

   Jurassic. 
  The 
  addition 
  of 
  Pecten 
  lens, 
  Sow., 
  var. 
  Morini, 
  Be 
  Lor., 
  and 
  

   Avicula 
  incequivalvis, 
  Sow., 
  to 
  the 
  list 
  of 
  Jurassic 
  forms 
  previously 
  

   determined, 
  strengthens 
  the 
  case 
  in 
  one 
  direction 
  ; 
  while 
  my 
  failure 
  

   to 
  find 
  Amm. 
  Astierianus, 
  D'Orb., 
  and 
  some 
  other 
  Neocomian 
  fossils 
  

   which 
  have 
  been 
  said 
  to 
  occur 
  in 
  this 
  part 
  of 
  the 
  section 
  has 
  the 
  

   same 
  effect 
  in 
  another 
  way, 
  by 
  weakening 
  the 
  evidence 
  on 
  which 
  

   the 
  beds 
  have 
  been 
  referred 
  to 
  the 
  Neocomian 
  *. 
  

  

  Should 
  the 
  Jurassic 
  age 
  of 
  these 
  Lateralis-beds 
  be 
  considered 
  as 
  

   established, 
  I 
  would 
  point 
  out 
  the 
  important 
  bearing 
  which 
  this 
  

   alteration 
  of 
  the 
  Speeton 
  section 
  will 
  have 
  on 
  the 
  beds 
  elsewhere 
  in 
  

   England 
  and 
  Northern 
  Europe 
  that 
  have 
  been 
  correlated 
  with 
  it. 
  In 
  

   the 
  lists 
  of 
  fossils 
  from 
  these 
  other 
  localities 
  {e. 
  ^.,the 
  numerous 
  ones 
  

   given 
  in 
  Judd's 
  later 
  paper 
  f, 
  or 
  those 
  in 
  the 
  recently 
  printed 
  Survey 
  

   Memoir 
  on 
  the 
  country 
  around 
  Lincoln 
  J) 
  one 
  constantly 
  notices 
  Bel. 
  

   lateralis 
  along 
  with 
  Bel. 
  jaculum 
  and 
  the 
  other 
  Neocomian 
  species. 
  

   It 
  would 
  become 
  necessary 
  to 
  revise 
  these 
  lists 
  and 
  find 
  out 
  what 
  

   forms 
  are 
  truly 
  associated 
  with 
  Bel. 
  lateralis 
  and 
  what 
  occur 
  in 
  

   higher 
  beds, 
  so 
  as 
  to 
  discover 
  whether 
  in 
  other 
  regions 
  also 
  it 
  may 
  

   be 
  advisable 
  to 
  draw 
  the 
  upper 
  limit 
  of 
  the 
  Jurassic 
  higher 
  in 
  the 
  

   series. 
  

  

  It 
  may 
  be 
  well 
  to 
  mention 
  in 
  this 
  connexion 
  that 
  in 
  the 
  upper 
  

   beds 
  at 
  Speeton, 
  in 
  the 
  zone 
  of 
  Belemnites 
  semicanaliculatus 
  ?, 
  there 
  

   is 
  one 
  form 
  among 
  the 
  varying 
  types 
  of 
  Belemnites 
  which 
  there 
  occur 
  

   that 
  bears 
  a 
  close 
  resemblance 
  to 
  Belemnites 
  lateralis, 
  and 
  has 
  some- 
  

   times 
  been 
  referred 
  to 
  that 
  species. 
  Close 
  examination 
  of 
  a 
  large 
  

   number 
  of 
  specimens, 
  however, 
  has 
  convinced 
  me 
  that 
  they 
  are 
  

   quite 
  distinct. 
  Where 
  this 
  form 
  occurs 
  alone 
  it 
  might 
  easily 
  be 
  

   mistaken 
  for 
  the 
  true 
  Bel. 
  lateralis, 
  and 
  this 
  might 
  lead 
  to 
  an 
  erro- 
  

   neous 
  classification 
  of 
  the 
  beds, 
  supposing 
  the 
  respective 
  horizons 
  of 
  

   the 
  fossils 
  to 
  be 
  as 
  at 
  Speeton. 
  

  

  * 
  By 
  far 
  the 
  most 
  important 
  evidence 
  yet 
  adduced 
  as 
  to 
  the 
  age 
  of 
  these 
  

   beds 
  has 
  been 
  furnished 
  since 
  this 
  was 
  written 
  by 
  the 
  Russian 
  geologists 
  Prof. 
  

   A. 
  Pavlow 
  and 
  M. 
  S. 
  Nikitin, 
  who 
  show 
  that 
  they 
  are 
  the 
  equivalents 
  of 
  the 
  

   " 
  Upper-Volga 
  beds 
  " 
  of 
  Southern 
  Russia 
  : 
  see 
  note 
  at 
  end 
  of 
  this 
  paper 
  (p. 
  608).- 
  

  

  t 
  Q. 
  J. 
  G-. 
  S. 
  vol. 
  xxvi. 
  pp. 
  326-347. 
  

  

  | 
  Survey 
  Memoir 
  : 
  On 
  the 
  country 
  around 
  Lincoln, 
  1888, 
  pp. 
  82-104. 
  

  

  