﻿SUBDIVISIONS 
  OP 
  THE 
  SPEETON 
  CLAY. 
  587 
  

  

  species, 
  not 
  yet 
  determined, 
  but 
  which 
  I 
  am 
  informed 
  is 
  not 
  Amm. 
  

   Astierianus, 
  is 
  common 
  in 
  the 
  bed 
  just 
  described 
  *. 
  Varieties 
  of 
  

   Exoygra 
  sinuata 
  occur 
  in 
  profusion, 
  and, 
  among 
  other 
  shells, 
  an 
  

   Astarte 
  named 
  by 
  the 
  early 
  collectors 
  Astarte 
  senecta 
  is 
  very 
  abun- 
  

   dant 
  ; 
  and 
  as 
  this 
  shell 
  is 
  rare 
  everywhere 
  except 
  in 
  these 
  pyritous 
  

   clays, 
  we 
  might 
  for 
  convenience 
  of 
  reference 
  speak 
  of 
  them 
  as 
  the 
  

   " 
  Astarte-TQeds" 
  

  

  The 
  fossils 
  of 
  the 
  Astarte-he&s 
  as 
  at 
  present 
  determined 
  will 
  be 
  

   found 
  separately 
  indicated 
  in 
  the 
  table 
  at 
  p. 
  591. 
  Many 
  additions 
  

   might 
  be 
  made 
  if 
  the 
  specimens 
  could 
  be 
  identified 
  without 
  removal. 
  

  

  Softer 
  pale 
  brownish 
  and 
  striped 
  beds 
  (D 
  8) 
  succeed, 
  containing 
  

   most 
  of 
  the 
  fossils 
  of 
  the 
  underlying 
  beds. 
  

  

  In 
  addition, 
  one 
  of 
  the 
  "coronated" 
  Ammonites 
  (Amm.Gravesianus, 
  

   D'Orb.) 
  occurs 
  in 
  a 
  nodular 
  band. 
  The 
  shell 
  seems 
  to 
  be 
  plen- 
  

   tiful 
  in 
  this 
  band, 
  but 
  it 
  is 
  generally 
  badly 
  preserved; 
  so 
  that 
  

   though 
  I 
  have 
  found 
  several 
  casts 
  of 
  the 
  deep 
  umbilicus, 
  which 
  form 
  

   curious 
  long 
  spirals, 
  and 
  other 
  fragments, 
  I 
  have 
  obtained 
  only 
  one 
  

   good 
  specimen. 
  The 
  position 
  of 
  this 
  Ammonite-bed 
  on 
  the 
  beach 
  is 
  

   marked 
  by 
  a 
  water-channel, 
  a 
  feature 
  that 
  may 
  be 
  owing 
  to 
  unequal 
  

   erosion 
  of 
  the 
  clays, 
  though 
  it 
  is 
  quite 
  as 
  probable 
  that 
  it 
  has 
  been 
  

   caused 
  by 
  raids 
  made 
  on 
  the 
  band 
  by 
  the 
  early 
  collectors, 
  who 
  evi- 
  

   dently 
  set 
  great 
  store 
  by 
  these 
  beautiful 
  Ammonites, 
  and 
  who 
  were 
  

   quite 
  capable 
  of 
  scooping 
  out 
  the 
  bed 
  in 
  their 
  searches, 
  just 
  as 
  they 
  

   have 
  served 
  the 
  famous 
  plant-bed 
  in 
  the 
  Oolites 
  at 
  Gristhorpe. 
  

   Leckenby, 
  it 
  will 
  be 
  noticed, 
  who 
  made 
  a 
  large 
  collection 
  of 
  these 
  

   forms, 
  has 
  recorded 
  the 
  fossil 
  from 
  this 
  horizon 
  under 
  the 
  names 
  Amm. 
  

   quadrifidus, 
  Bean, 
  and 
  Amm. 
  cavaticus, 
  Bean 
  (see 
  diagram 
  fig. 
  2). 
  

  

  The 
  thin 
  band 
  of 
  clay 
  with 
  nodules 
  which 
  caps 
  these 
  striped 
  beds 
  

   includes 
  here 
  and 
  there 
  lenticular 
  masses 
  of 
  soft 
  gritty 
  ferruginous 
  

   stone. 
  Higher 
  in 
  the 
  section 
  these 
  ferruginous 
  stony 
  bands 
  are 
  

   frequent, 
  and 
  more 
  persistent 
  in 
  character, 
  and 
  are 
  a 
  distinctive 
  

   feature 
  of 
  that 
  portion 
  of 
  the 
  clay 
  ; 
  but 
  this 
  is 
  the 
  only 
  example 
  of 
  

   this 
  structure 
  I 
  have 
  observed 
  in 
  the 
  zone 
  of 
  Bel. 
  latercdis. 
  

  

  Dark 
  blue 
  or 
  brownish 
  clay 
  about 
  4 
  feet 
  thick 
  lies 
  above 
  this 
  band 
  

   and 
  reaches 
  to 
  the 
  top 
  of 
  the 
  zone. 
  This 
  clay 
  (D 
  2) 
  is 
  slightly 
  gritty 
  

   in 
  texture 
  and 
  contains 
  a 
  quantity 
  of 
  dark 
  green 
  and 
  black 
  grains, 
  

   probably 
  of 
  glauconite. 
  It 
  is 
  crowded 
  with 
  Bel. 
  lateralis 
  and 
  some 
  

   other 
  fossils, 
  and 
  has 
  a 
  plentiful 
  sprinkling 
  of 
  brown 
  " 
  potato-nodules 
  " 
  

   and 
  black 
  and 
  brown 
  coprolitic 
  stones. 
  These 
  latter 
  become 
  more 
  

   abundant 
  towards 
  the 
  top, 
  and 
  of 
  larger 
  size 
  than 
  anywhere 
  else 
  in 
  

   the 
  section. 
  One 
  lump 
  measured 
  3 
  inches 
  x 
  2 
  x 
  1, 
  and 
  I 
  have 
  seen 
  

   others 
  even 
  exceeding 
  this. 
  Some 
  of 
  these 
  stones, 
  especially 
  the 
  

   larger 
  ones, 
  occasionally 
  present 
  a 
  striking 
  peculiarity 
  in 
  being 
  on 
  

   some 
  sides 
  quite 
  angular. 
  Usually 
  they 
  are 
  more 
  or 
  less 
  rounded 
  and 
  

   curiously 
  eroded, 
  as 
  though 
  by 
  marine 
  organisms, 
  and 
  are 
  sometimes 
  

   pitted 
  by 
  tubular 
  holes 
  that 
  look 
  like 
  P7ioZas-borings 
  ; 
  but 
  it 
  is 
  not 
  

  

  * 
  Prof. 
  A. 
  Paylow 
  has 
  recently 
  stated 
  his 
  belief 
  that 
  these 
  small 
  forms 
  may 
  

   represent 
  species 
  well 
  known 
  in 
  .Russia 
  as 
  Olvostephanus 
  subditus, 
  Traut., 
  and 
  

   Oxynotyceras 
  catenulatum, 
  Fisch. 
  (see 
  note 
  at 
  p. 
  608). 
  

  

  