﻿618 
  OX 
  THE 
  SUBDIVISIONS 
  OF 
  THE 
  SPEETOX 
  CLAY. 
  

  

  conformity 
  here 
  ; 
  at 
  least 
  there 
  was 
  a 
  palaeontological 
  unconformity, 
  

   if 
  not 
  a 
  stratigraphical 
  one. 
  

  

  Mr. 
  Hedlestox 
  also 
  alluded 
  to 
  the 
  terrible 
  confusion 
  in 
  Filey 
  

   Bay, 
  and 
  to 
  the 
  difficulty 
  of 
  obtaining 
  more 
  than 
  a 
  glimpse 
  of 
  the 
  

   rich 
  fossil 
  beds 
  of 
  the 
  Speeton 
  Clay. 
  The 
  section 
  was 
  remarkable 
  

   in 
  the 
  apparent 
  sequence 
  from 
  Upper 
  Jurassic 
  through 
  Lower 
  Cre- 
  

   taceous 
  into 
  Upper 
  Cretaceous 
  ; 
  but 
  he 
  thought 
  there 
  existed 
  un- 
  

   conformities 
  in 
  time, 
  as 
  indicated 
  by 
  change 
  of 
  fauna, 
  which 
  were 
  

   sometimes 
  more 
  important 
  than 
  those 
  which 
  made 
  a 
  greater 
  im- 
  

   pression 
  on 
  the 
  eye. 
  Such 
  were 
  frequently 
  marked 
  by 
  nodule-beds, 
  

   as 
  was 
  the 
  case 
  at 
  the 
  top 
  and 
  bottom 
  of 
  the 
  Author 
  s 
  Lateralis-zone. 
  

   Underlying 
  the 
  lowest 
  of 
  these 
  nodule-beds 
  the 
  clays 
  were 
  un- 
  

   doubtedly 
  Kimeridgian, 
  whilst 
  above 
  it 
  was 
  an 
  almost 
  total 
  change 
  

   of 
  fauna. 
  He 
  did 
  not 
  believe 
  in 
  the 
  existence 
  of 
  true 
  Portlandian 
  

   beds 
  in 
  Yorkshire. 
  These 
  were 
  really 
  limited 
  in 
  extent, 
  but 
  there 
  

   was 
  a 
  large 
  part 
  of 
  the 
  equivalents 
  of 
  our 
  Kimeridge 
  Clay 
  which 
  were 
  

   called 
  Portlandian 
  by 
  continental 
  geologists. 
  Much 
  of 
  this 
  was 
  below 
  

   the 
  Upper 
  Kimeridge. 
  Hence 
  the 
  Lateralis-zone 
  could 
  not 
  be 
  on 
  

   that 
  horizon. 
  What, 
  then, 
  is 
  this 
  zone 
  with 
  the 
  so-called 
  Aram. 
  Grave- 
  

   sian 
  us 
  and 
  Am 
  ra. 
  gigas 
  in 
  its 
  uppermost 
  portion 
  ? 
  There 
  was 
  nothing 
  

   like 
  it 
  in 
  this 
  country 
  that 
  he 
  knew 
  of, 
  and 
  it 
  appeared 
  that 
  we 
  must 
  

   go 
  to 
  Eussia 
  for 
  the 
  analogues. 
  The 
  top 
  of 
  Mr. 
  Lamplugh's 
  section 
  

   was 
  equally 
  interesting, 
  as 
  indicating, 
  amongst 
  other 
  things, 
  the 
  

   probability 
  of 
  the 
  Bed 
  Chalk 
  of 
  Speeton 
  being 
  only 
  of 
  Upper- 
  

   Gault 
  age. 
  The 
  paper 
  was 
  another 
  instance 
  of 
  the 
  value 
  of 
  close 
  

   observations 
  conducted 
  over 
  a 
  long 
  period 
  of 
  time. 
  

  

  Mr. 
  Hekeies 
  could 
  confirm 
  Mr. 
  Lamplugh's 
  account 
  of 
  the 
  so- 
  

   called 
  " 
  Middle 
  Kimeridge 
  " 
  beds. 
  He 
  failed 
  to 
  understand 
  why 
  

   the 
  Middle 
  ^seocomian 
  should 
  be 
  abolished. 
  He 
  alluded 
  to 
  some 
  

   beds 
  on 
  the 
  shore, 
  which 
  by 
  their 
  fossils 
  seemed 
  to 
  indicate 
  a 
  passage 
  

   from 
  the 
  Upper 
  Kimeridge 
  to 
  the 
  Bel. 
  lateralis-'beds. 
  

  

  The 
  Aethoe, 
  in 
  reply, 
  spoke 
  of 
  the 
  advantage 
  of 
  using 
  Belemnites 
  

   for 
  his 
  main 
  divisions, 
  as 
  the 
  types 
  in 
  this 
  case 
  were 
  so 
  distinct, 
  and 
  

   120 
  feet 
  of 
  beds 
  were 
  characterized 
  by 
  the 
  easily 
  recognizable 
  

   B.jaculum. 
  He 
  thought 
  the 
  beds 
  were 
  more 
  easily 
  identified 
  in 
  

   this 
  way, 
  though 
  the 
  range 
  of 
  Ammonites 
  (which 
  often 
  overlapped 
  

   each 
  other) 
  had 
  been 
  traced 
  as 
  far 
  as 
  ne 
  was 
  able. 
  With 
  the 
  Belem- 
  

   nites 
  also 
  came 
  in 
  the 
  principal 
  changes 
  in 
  the 
  fauna. 
  There 
  was 
  

   a 
  change 
  of 
  fauna 
  several 
  times 
  in 
  the 
  section, 
  and 
  sometimes 
  

   without 
  nodular 
  bands. 
  The 
  Kimeridge 
  beds 
  in 
  Lincolnshire 
  were 
  

   similar, 
  the 
  Xeocomian 
  dissimilar. 
  Besides 
  the 
  supposed 
  remanie 
  

   Portlandian 
  forms 
  in 
  the 
  lower 
  coprolite-bed, 
  there 
  was 
  a 
  passage 
  

   upwards 
  of 
  certain 
  Jurassic 
  fossils, 
  such 
  as 
  Avicula 
  incequivalvis 
  and 
  

   Pecten 
  lens. 
  The 
  Speeton 
  " 
  Portlandiaus 
  " 
  are 
  believed 
  to 
  represent 
  

   the 
  " 
  Upper 
  Volga 
  beds" 
  of 
  the 
  Russians. 
  With 
  respect 
  to 
  the 
  Gault 
  

   forms, 
  the 
  gradual 
  change 
  is 
  a 
  good 
  evidence 
  in 
  support 
  of 
  passage. 
  

  

  