﻿600 
  ME. 
  G. 
  W. 
  LAMPLTJGH 
  ON 
  THE 
  

  

  sidered 
  a 
  variety, 
  though 
  I 
  think 
  it 
  deserves 
  specific 
  recognition 
  

   (see 
  Appendix, 
  p. 
  611). 
  

  

  The 
  Belemnites 
  in 
  these 
  upper 
  beds 
  include 
  several 
  distinct 
  forms, 
  

   about 
  the 
  identification 
  of 
  which 
  there 
  is 
  great 
  uncertainty. 
  Many 
  

   of 
  them 
  have 
  been 
  referred 
  to 
  Bel. 
  semicanaliculatiis, 
  but 
  none 
  are 
  

   typical 
  forms 
  of 
  that 
  species, 
  and 
  Judd, 
  who 
  so 
  named 
  them, 
  has 
  

   since 
  stated 
  * 
  that 
  they 
  are 
  the 
  Bel. 
  brwisvicensis, 
  Yon 
  Stronib. 
  

   It 
  is 
  probable 
  that 
  some 
  of 
  these 
  forms 
  will 
  be 
  found 
  to 
  have 
  re- 
  

   stricted 
  ranges, 
  but 
  this 
  has 
  not 
  yet 
  been 
  demonstrated, 
  and, 
  in 
  spite 
  

   of 
  the 
  variety, 
  these 
  various 
  types 
  taken 
  together 
  form 
  a 
  well-marked 
  

   group 
  totally 
  distinct 
  from 
  those 
  of 
  the 
  lower 
  beds. 
  Being 
  more- 
  

   over 
  by 
  far 
  the 
  most 
  plentiful 
  fossils, 
  they 
  afford 
  the 
  readiest 
  means 
  

   of 
  describing 
  and 
  identifying 
  the 
  upper 
  portion 
  of 
  the 
  section 
  : 
  

   and 
  I 
  therefore 
  propose, 
  pending 
  more 
  decisive 
  determination, 
  to 
  

   apply 
  provisionally 
  to 
  this 
  part 
  of 
  the 
  clay 
  the 
  older 
  and 
  better 
  

   known 
  name 
  of 
  the 
  species, 
  and 
  to 
  speak 
  of 
  it 
  as 
  the 
  Zone 
  of 
  Bel. 
  

   semicanaliculatiis 
  ? 
  

  

  It 
  is 
  rare 
  that 
  opportunities 
  for 
  studying 
  this 
  zone 
  in 
  detail 
  

   present 
  themselves, 
  and 
  I 
  can 
  give 
  no 
  complete 
  section, 
  as 
  my 
  know- 
  

   ledge 
  of 
  it 
  is 
  still 
  only 
  partial. 
  The 
  beach 
  south 
  of 
  Speeton 
  Gap, 
  

   where 
  these 
  beds 
  mainly 
  crop 
  out, 
  is 
  very 
  rarely 
  stripped, 
  and 
  even 
  

   when 
  exposures 
  do 
  occur 
  they 
  are 
  often 
  encumbered 
  by 
  the 
  large 
  

   chalk 
  boulders 
  which 
  here 
  strew 
  the 
  beach, 
  and 
  which 
  not 
  

   only 
  actually 
  hide 
  the 
  beds, 
  but 
  have 
  also 
  been 
  so 
  pounded 
  over 
  

   them 
  by 
  the 
  sea 
  as 
  to 
  cause 
  an 
  obscure 
  and 
  battered 
  surface. 
  I 
  

   did 
  indeed, 
  early 
  in 
  1881, 
  see 
  a 
  wide 
  stretch 
  of 
  the 
  beds 
  to 
  the 
  

   southward 
  of 
  the 
  Gap, 
  but 
  under 
  conditions 
  so 
  unfavourable 
  that 
  I 
  

   could 
  do 
  little 
  more 
  than 
  note 
  the 
  direction 
  of 
  their 
  strike, 
  and 
  that 
  

   they 
  consisted 
  of 
  banded 
  clays 
  with 
  lines 
  of 
  large 
  nodules 
  : 
  and 
  

   when 
  I 
  went 
  again 
  in 
  better 
  weather 
  to 
  try 
  to 
  do 
  more, 
  the 
  place 
  

   was 
  covered. 
  

  

  I 
  still 
  think, 
  however, 
  that 
  with 
  patience 
  it 
  may 
  be 
  possible 
  some 
  

   time 
  to 
  work 
  out 
  this 
  part 
  of 
  the 
  section 
  also. 
  Meanwhile 
  I 
  give 
  

   a 
  section 
  (in 
  fig. 
  6) 
  of 
  the 
  beds 
  at 
  the 
  base 
  of 
  the 
  zone, 
  from 
  

   measurements 
  at 
  the 
  foot 
  of 
  Black 
  Cliff, 
  in 
  part 
  corroborated 
  by 
  

   an 
  exposure 
  on 
  the 
  shore. 
  

  

  There 
  is 
  by 
  no 
  means 
  the 
  decisive 
  change 
  of 
  fauna 
  here 
  that 
  occurs 
  

   at 
  the 
  base 
  of 
  the 
  Jaculiim-zone 
  ; 
  but 
  proceeding 
  upwards 
  we 
  find 
  

   many 
  new 
  species 
  appearing, 
  which 
  shows, 
  equally 
  with 
  the 
  dis- 
  

   appearance 
  of 
  many 
  of 
  the 
  old 
  forms, 
  the 
  changing 
  character 
  of 
  

   the 
  fauna, 
  although 
  there 
  are 
  examples 
  of 
  species 
  overlapping 
  in 
  

   both 
  directions 
  at 
  the 
  junction. 
  

  

  The 
  clays 
  in 
  this 
  section 
  are 
  decidedly 
  darker 
  than 
  in 
  any 
  mass 
  

   of 
  similar 
  thickness 
  below, 
  but 
  yet 
  include, 
  besides 
  several 
  narrower 
  

   ones, 
  one 
  broad 
  pale 
  band 
  with 
  two 
  layers 
  of 
  large 
  nodules. 
  The 
  

   nodules 
  throughout 
  the 
  entire 
  zone 
  are 
  generally 
  larger 
  than 
  

   those 
  of 
  the 
  lower 
  divisions, 
  and 
  are 
  paler 
  in 
  colour, 
  probably 
  con- 
  

  

  * 
  In 
  a 
  footnote 
  to 
  T. 
  Davidson's 
  " 
  Notes 
  on 
  Continental 
  Geology," 
  Geol. 
  

   Mag. 
  (1869), 
  vol. 
  vi. 
  p. 
  263. 
  

  

  