﻿SUBDIVISIONS 
  OF 
  THE 
  SPEETON 
  CLAY. 
  585 
  

  

  Leckenby 
  meant 
  by 
  the 
  " 
  Coprolite-band 
  " 
  was 
  not 
  the 
  same 
  hori- 
  

   zon 
  as 
  the 
  " 
  Coprolite-bed 
  " 
  of 
  Jndd, 
  that 
  he 
  indicated 
  by 
  that 
  

   name 
  the 
  very 
  striking 
  layer 
  of 
  limestone-nodules 
  with 
  scattered 
  

   coprolites, 
  presently 
  to 
  be 
  described 
  in 
  this 
  paper 
  as 
  " 
  the 
  Compound 
  

   Nodular 
  Band." 
  

  

  The 
  existence 
  of 
  this 
  higher 
  band 
  was 
  apparently 
  unknown 
  to 
  

   Judd, 
  who 
  seems 
  to 
  have 
  had 
  no 
  doubt 
  that 
  the 
  bed 
  mentioned 
  

   by 
  Leckenby 
  was 
  the 
  one 
  known 
  to 
  him. 
  However, 
  as 
  Leckenby's 
  

   section 
  and 
  my 
  own 
  researches 
  show, 
  the 
  coronated 
  Ammonites 
  really 
  

   occur 
  in 
  the 
  hard 
  pyritous 
  clays 
  which 
  Judd 
  himself 
  saw 
  and, 
  not 
  

   knowing 
  this, 
  described 
  as 
  the 
  " 
  Zone 
  of 
  Amm. 
  Astierianus." 
  And 
  

   thus 
  it 
  happens 
  that 
  the 
  " 
  Portlandian 
  " 
  of 
  Leckenby 
  is 
  part 
  of 
  the 
  

   " 
  Lower 
  Neocomian 
  " 
  of 
  Judd, 
  and 
  the 
  hypothetical 
  beds 
  placed 
  by 
  

   the 
  latter 
  author 
  below 
  the 
  lower 
  Coprolite-bed 
  have 
  no 
  existence. 
  

  

  In 
  the 
  diagram 
  (fig. 
  2, 
  facing 
  p. 
  618) 
  the 
  section 
  given 
  by 
  

   Leckenby 
  is 
  arranged 
  side 
  by 
  side 
  with 
  Judd's 
  and 
  my 
  own, 
  so 
  as 
  

   to 
  show 
  these 
  results. 
  - 
  

  

  D. 
  Zone 
  of 
  Belemnites 
  lateralis, 
  Phil. 
  (fig. 
  4). 
  

  

  Though 
  I 
  have 
  described 
  the 
  Coprolite-bed 
  separately 
  because 
  of 
  

   the 
  importance 
  attached 
  to 
  it 
  by 
  previous 
  authors, 
  there 
  is 
  really 
  not 
  

   much 
  reason 
  for 
  separating 
  it 
  from 
  the 
  overlying 
  clays, 
  of 
  which 
  it 
  

   may 
  be 
  considered 
  as 
  the 
  base. 
  

  

  Immediately 
  above 
  the 
  " 
  Coprolite-bed 
  " 
  we 
  have 
  about 
  10 
  inches 
  of 
  

   hard 
  blackish 
  shale 
  (D 
  8), 
  which 
  does 
  not 
  differ 
  much 
  in 
  appearance 
  

   from 
  the 
  bituminous 
  shales 
  below(F),so 
  that 
  Leckenby's 
  description 
  of 
  

   this 
  " 
  Coprolite-bed 
  " 
  as 
  " 
  a 
  seam 
  of 
  coprolitic 
  nodules 
  " 
  in 
  a 
  " 
  stratum 
  

   of 
  dark 
  brown 
  shaly 
  clay 
  " 
  (Bed 
  6 
  of 
  his 
  section) 
  is 
  really 
  justified. 
  

  

  In 
  this 
  shale 
  I 
  have 
  not 
  detected 
  any 
  fossils 
  except 
  a 
  fragment 
  of 
  

   bone 
  and 
  a 
  few 
  greatly 
  eroded 
  specimens 
  of 
  Belemnites. 
  These 
  

   latter 
  are 
  beyond 
  specific 
  determination, 
  but 
  what 
  is 
  left 
  of 
  them 
  

   shows 
  that 
  they 
  are 
  not 
  far 
  removed 
  from 
  B. 
  lateralis 
  ; 
  if 
  not 
  

   actually 
  of 
  that 
  species, 
  they 
  must, 
  like 
  those 
  in 
  the 
  Coprolite-bed, 
  

   belong 
  to 
  an 
  allied 
  form. 
  

  

  In 
  the 
  overlying 
  band 
  of 
  greenish-black 
  shale 
  undoubted 
  speci- 
  

   mens 
  of 
  Bel. 
  lateralis 
  can 
  be 
  readily 
  identified. 
  From 
  this 
  point 
  

   the 
  species 
  occurs 
  abundantly, 
  and 
  remains 
  predominant 
  up 
  to 
  the 
  

   Compound 
  Nodular 
  Band. 
  Figure 
  4 
  gives 
  the 
  detailed 
  section 
  of 
  the 
  

   zone 
  from 
  top 
  to 
  bottom. 
  

  

  The 
  only 
  other 
  fossils 
  I 
  have 
  noticed 
  in 
  the 
  band 
  are 
  a 
  few 
  shells 
  

   in 
  a 
  fragmentary 
  condition 
  ; 
  but 
  the 
  bed 
  also 
  contains 
  a 
  thin 
  

   sprinkling 
  of 
  small 
  black 
  pebbles, 
  probably 
  phosphatic, 
  generally 
  

   not 
  larger 
  than 
  peas. 
  

  

  The 
  variegated 
  and 
  banded 
  clays 
  which 
  lie 
  above 
  serve 
  as 
  

   passage-beds 
  into 
  the 
  very 
  conspicuous 
  pale 
  band 
  (D 
  6), 
  which 
  

   forms 
  a 
  striking 
  feature 
  in 
  the 
  section. 
  In 
  the 
  latter 
  bed 
  the 
  clay 
  

   towards 
  the 
  centre 
  of 
  the 
  band 
  becomes 
  very 
  firm 
  and 
  hard 
  — 
  indeed 
  

   Leckenby, 
  who 
  noticed 
  the 
  " 
  remarkable 
  line 
  of 
  demarcation 
  " 
  which 
  

   the 
  bed 
  makes, 
  describes 
  it 
  as 
  an 
  " 
  argillaceous 
  stone." 
  It 
  is 
  curi- 
  

   ously 
  mottled, 
  in 
  its 
  lower 
  part 
  especially, 
  with 
  flattened 
  tubular 
  

  

  