﻿588 
  MR. 
  O. 
  W. 
  LAJAPLTJGH 
  OX 
  THE 
  

  

  uncommon 
  to 
  find 
  a 
  stone 
  presenting 
  this 
  worn 
  appearance 
  in 
  one 
  

   portion 
  cut 
  suddenly 
  across 
  by 
  a 
  sharp-angled 
  fracture, 
  of 
  which 
  the 
  

   face 
  is 
  apparently 
  quite 
  fresh 
  and 
  unworn. 
  The 
  stones 
  often 
  have 
  

   a 
  distinct 
  tendency 
  to 
  break 
  into 
  cubical 
  fragments 
  after 
  the 
  fashion 
  

   of 
  septaria 
  ; 
  but 
  I 
  have 
  satisfied 
  myself 
  that 
  in 
  the 
  cases 
  I 
  have 
  just 
  

   described 
  the 
  fracture 
  has 
  not 
  taken 
  place 
  as 
  the 
  stone 
  lay 
  in 
  the 
  

   clay, 
  but 
  that 
  it 
  was 
  deposited 
  there 
  in 
  this 
  imperfect 
  condition. 
  

   In 
  one 
  instance 
  one 
  of 
  these 
  semi-angular 
  stones, 
  3^ 
  inches 
  in 
  

   length, 
  formed 
  part 
  of 
  the 
  outer 
  whorl 
  of 
  a 
  large 
  Ammonite 
  re- 
  

   sembling 
  Amm. 
  hiplex, 
  but 
  in 
  no 
  other 
  case 
  have 
  I 
  found 
  any 
  indica- 
  

   tion 
  of 
  fossils 
  in 
  them. 
  These 
  stones 
  are 
  still 
  more 
  plentiful 
  just 
  

   above, 
  in 
  the 
  compound 
  nodular-band 
  (D 
  1). 
  It 
  is 
  not 
  easy 
  to 
  

   understand 
  how 
  pebbles 
  of 
  this 
  size 
  with 
  unworn 
  angles 
  could 
  be 
  

   deposited 
  in 
  fine 
  clay, 
  and 
  I 
  shall 
  revert 
  to 
  the 
  matter 
  in 
  a 
  later 
  

   portion 
  of 
  my 
  paper. 
  

  

  Imbedded 
  in 
  the 
  upper 
  portion 
  of 
  this 
  clay 
  is 
  the 
  very 
  clearly- 
  

   marked 
  line 
  of 
  curious 
  nodules 
  (D 
  1) 
  which 
  forms 
  a 
  peculiar 
  feature 
  

   of 
  the 
  section. 
  The 
  smaller 
  of 
  these 
  nodules 
  are 
  of 
  the 
  usual 
  oval, 
  

   brown 
  character 
  ; 
  but 
  these 
  are 
  subordinate 
  to 
  larger 
  concretions, 
  

   evidently 
  of 
  a 
  later 
  growth, 
  which 
  form 
  large 
  irregular 
  flattened- 
  

   oval 
  masses 
  of 
  limestone 
  of 
  a 
  pale 
  grey 
  or 
  bluish 
  tint. 
  These 
  

   masses 
  generally 
  surround 
  and 
  include 
  several 
  of 
  the 
  smaller 
  " 
  potato- 
  

   nodules 
  " 
  along 
  with 
  black 
  coprolite-stones 
  and 
  fossils 
  of 
  various 
  

   kinds. 
  In 
  some 
  cases 
  an 
  examination 
  shows 
  that 
  the 
  smaller 
  

   nodules 
  with 
  their 
  black 
  pyritous 
  interior 
  and 
  brown 
  outer 
  coating 
  

   have 
  not 
  only 
  been 
  completely 
  developed, 
  but 
  have 
  also 
  suffered 
  a 
  

   certain 
  amount 
  of 
  marine 
  erosion 
  before 
  the 
  concretionary 
  action 
  

   recommenced 
  which 
  formed 
  the 
  large 
  limestone 
  masses. 
  

  

  Nevertheless, 
  this 
  renewal 
  of 
  the 
  concretionary 
  action 
  has 
  not 
  

   taken 
  place 
  at 
  a 
  later 
  date 
  than 
  the 
  formation 
  of 
  the 
  seam. 
  It 
  is 
  

   evident 
  that 
  the 
  deposition 
  was 
  at 
  this 
  period 
  extremely 
  slow, 
  and 
  

   thus 
  allowed 
  the 
  action 
  to 
  take 
  place 
  contemporaneously, 
  since 
  the 
  

   larger 
  masses 
  themselves 
  often 
  show 
  distinct 
  signs 
  of 
  weathering 
  

   and 
  decay 
  as 
  though 
  they 
  had 
  been 
  exposed 
  on 
  an 
  open 
  sea-bottom. 
  

   The 
  whole 
  aspect 
  of 
  the 
  seam 
  as 
  well 
  as 
  the 
  evidence 
  of 
  the 
  fossils 
  

   indicates 
  a 
  pause 
  in 
  the 
  deposition 
  of 
  the 
  series. 
  There 
  is, 
  however, 
  

   not 
  the 
  slightest 
  sign 
  of 
  an 
  unconformity. 
  

  

  Belemnites 
  lateralis 
  occurs 
  in 
  large 
  numbers 
  both 
  in 
  the 
  nodules 
  and 
  

   in 
  the 
  clay 
  surrounding 
  them 
  : 
  but 
  here 
  the 
  species 
  abruptly 
  dies 
  out, 
  

   and 
  I 
  have 
  not 
  found 
  any 
  specimen 
  of 
  this 
  species 
  in 
  higher 
  beds. 
  

   Its 
  place 
  is 
  taken 
  by 
  Bel. 
  jaculam, 
  which 
  sets 
  in 
  suddenly 
  and 
  

   abundantly 
  just 
  above 
  the 
  nodules 
  and 
  reigns 
  supreme 
  and 
  all 
  but 
  

   alone 
  throughout 
  the 
  succeeding 
  120 
  feet 
  of 
  clay. 
  There 
  may 
  be 
  a 
  

   slight 
  intermingling 
  where 
  the 
  two 
  meet, 
  as 
  their 
  horizons 
  seem 
  

   somewhat 
  to 
  overlap, 
  though 
  it 
  is 
  rarely 
  that 
  one 
  can 
  find 
  them 
  

   actually 
  together. 
  It 
  is 
  possible 
  that 
  the 
  guards 
  of 
  Bel. 
  lateralis 
  

   may 
  have 
  lain 
  exposed 
  for 
  some 
  time 
  on 
  the 
  sea-bottom 
  like 
  some 
  

   of 
  the 
  nodules, 
  and 
  the 
  occasional 
  intermingling 
  need 
  not 
  neces- 
  

   sarily 
  indicate 
  that 
  the 
  two 
  forms 
  were 
  alive 
  together 
  in 
  the 
  same 
  

  

  