﻿I48 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  cester, 
  at 
  Honeybourne 
  in 
  Warwickshire, 
  at 
  Lyme 
  Eegis, 
  and 
  at 
  Robin 
  

   Hood's 
  Bay 
  we 
  have 
  the 
  same 
  lithological 
  conditions, 
  chiefly 
  com- 
  

   prising 
  dark 
  pyritous 
  shales, 
  the 
  absence 
  of 
  limestones 
  being 
  a 
  

   marked 
  feature. 
  

  

  The 
  coral 
  fauna 
  of 
  the 
  JEgoceras-angulatum 
  , 
  or 
  Infra-Lias, 
  beds, 
  we 
  

   have 
  seen, 
  numbered 
  nearly 
  50 
  species 
  ; 
  but 
  the 
  total 
  number 
  of 
  

   species 
  known 
  in 
  the 
  succeeding 
  6 
  zones 
  is 
  only 
  13 
  : 
  6 
  of 
  these 
  are 
  

   Monilivaltice 
  and 
  4 
  Isastrcece, 
  Septastrcea, 
  Lepidophyllia, 
  and 
  Cya- 
  

   thocoenia 
  having 
  only 
  one 
  species 
  each. 
  

  

  No 
  coral 
  fauna 
  occurs 
  in 
  the 
  zone 
  of 
  JEgoceras 
  Henleyi, 
  or 
  in 
  

   those 
  of 
  Amaltheus 
  margaritatus 
  and 
  A. 
  spinatus, 
  although 
  all 
  three 
  

   groups 
  of 
  strata 
  characterized 
  by 
  these 
  three 
  species 
  are 
  completely 
  

   developed 
  in 
  England, 
  especially 
  the 
  two 
  last 
  named. 
  I 
  shall 
  have 
  

   occasion 
  to 
  notice 
  these 
  zones 
  in 
  detail 
  in 
  my 
  remarks 
  upon 
  the 
  

   distribution 
  of 
  the 
  Cephalopoda 
  ; 
  it 
  is 
  essential, 
  however, 
  to 
  notice 
  

   them 
  here 
  under 
  the 
  Lias 
  for 
  the 
  purpose 
  of 
  illustrating 
  the 
  

   distribution 
  of 
  the 
  Actinozoa. 
  

  

  Pour 
  of 
  the 
  zones 
  into 
  which 
  the 
  Upper 
  Lias 
  can 
  be 
  readily 
  

   divided 
  — 
  viz. 
  the 
  zones 
  of 
  Harpoceras 
  serpentinum, 
  H. 
  bifrons, 
  Lyto- 
  

   ceras 
  jurense, 
  and 
  Harp, 
  opalinum 
  — 
  contain 
  only 
  two 
  species 
  of 
  

   corals 
  throughout 
  their 
  known 
  range 
  ; 
  as 
  before 
  stated, 
  these 
  are 
  

   Montlivaltia 
  tuberculata 
  and 
  Trocliocyathus 
  primus*. 
  The 
  dark 
  

   clays 
  and 
  sandy 
  beds 
  in 
  Yorkshire, 
  with 
  Steplianoceras 
  commune, 
  

   Harpoceras 
  falciferum, 
  Stephanoceras 
  crassum, 
  Harpoceras 
  elegans, 
  

   and 
  many 
  others, 
  are 
  rich 
  in 
  all 
  groups 
  but 
  the 
  Ccelenterata. 
  

  

  The 
  coral 
  fauna 
  then 
  of 
  the 
  3 
  divisions 
  of 
  the 
  Lias 
  is 
  a 
  singular 
  

   illustration 
  of 
  stratigraphical 
  distribution 
  and 
  physical 
  conditions 
  : 
  the 
  

   Lower 
  Lias, 
  and 
  chiefly 
  the 
  lowest 
  zones 
  of 
  the 
  group, 
  have 
  yielded 
  

   72 
  species 
  representing 
  13 
  genera 
  ; 
  the 
  Middle 
  Lias 
  only 
  8 
  species 
  

   belonging 
  to 
  6 
  genera 
  : 
  and 
  the 
  Upper 
  Lias 
  2 
  genera 
  and 
  2 
  species. 
  

   We 
  have 
  no 
  reason 
  to 
  suppose 
  that 
  many 
  other 
  species 
  occur 
  ; 
  though, 
  

   looking 
  at 
  the 
  development 
  of 
  the 
  Upper 
  Lias, 
  laterally 
  and 
  vertically, 
  

   in 
  Britain, 
  they 
  may 
  be 
  expected 
  to 
  be 
  more 
  abundant 
  : 
  be 
  it 
  re- 
  

   membered 
  that 
  the 
  seas 
  of 
  Britain 
  at 
  present 
  contain 
  but 
  one 
  or 
  two 
  

   species, 
  and 
  their 
  habitats 
  are 
  not 
  congenial 
  for 
  preservation. 
  

  

  Echlnodermata. 
  — 
  The 
  Jurassic 
  rocks 
  of 
  the 
  British 
  Islands 
  are 
  

   known, 
  up 
  to 
  the 
  present 
  time, 
  to 
  contain 
  47 
  genera 
  and 
  216 
  species 
  : 
  

   the 
  Lias, 
  in 
  all 
  the 
  three 
  divisions, 
  20 
  genera 
  and 
  53 
  species. 
  

   In 
  the 
  Lower 
  Lias 
  11 
  genera 
  and 
  15 
  species 
  occur 
  ; 
  in 
  the 
  Middle 
  

   14 
  genera 
  and 
  29 
  species; 
  and 
  in 
  the 
  Upper 
  8 
  genera 
  and 
  14 
  species. 
  

   Eew 
  species 
  occur 
  in 
  any 
  of 
  the 
  Lias 
  genera 
  of 
  Echinodermata 
  

   except 
  Pentacrinus, 
  of 
  which 
  2 
  occur 
  in 
  the 
  Lower, 
  9 
  in 
  the 
  Middle, 
  

   and 
  6 
  in 
  the 
  Upper 
  Lias 
  ; 
  with 
  this 
  exception, 
  no 
  genus 
  in 
  either 
  of 
  

   the 
  three 
  divisions 
  is 
  represented 
  by 
  more 
  than 
  5 
  species, 
  the 
  

   number 
  possessed 
  by 
  Opluoderma. 
  The 
  remaining 
  10 
  genera 
  are 
  

   very 
  sparingly 
  represented. 
  

  

  * 
  Trocliocyathus 
  Moorei 
  is 
  a 
  doubtful 
  species. 
  

  

  