﻿I46 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  In 
  Dorsetshire 
  it 
  occurs 
  below 
  the 
  Davaei 
  series. 
  Oppel, 
  in 
  his 
  

   ' 
  Die 
  Juraformation 
  : 
  die 
  Schichten 
  des 
  Ammonites 
  Ibex,' 
  p. 
  122, 
  and 
  

   Wright, 
  " 
  Ibex-bed" 
  (Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xiv. 
  p. 
  25), 
  in 
  his 
  

   table, 
  shows 
  the 
  correlation 
  of 
  the 
  beds 
  on 
  the 
  continent 
  with 
  

   those 
  of 
  Gloucestershire 
  and 
  Scotland 
  (Skye). 
  

  

  Upper 
  Lias. 
  — 
  Only 
  two 
  species 
  of 
  Actinozoa 
  have 
  as 
  yet 
  been 
  de- 
  

   tected 
  in 
  the 
  Upper 
  Lias 
  of 
  the 
  British 
  Islands 
  ; 
  they 
  are 
  Monilivaltia 
  

   tuberculata 
  and 
  TrocJiocyathus 
  primus. 
  The 
  last-named 
  is 
  from 
  the 
  

   Ilminster 
  beds 
  ; 
  and 
  Monilivaltia 
  tuberculata 
  occurs 
  at 
  Adderbury, 
  

   near 
  Banbury. 
  

  

  The 
  Actinozoa 
  of 
  the 
  Lias 
  therefore 
  essentially 
  belong 
  to 
  the 
  lower 
  

   division 
  and 
  to 
  the 
  lowest 
  zones. 
  The 
  zones 
  of 
  JEgoceras 
  planorbis, 
  

   JE. 
  angulatum, 
  Arietites 
  Bucldancli, 
  A. 
  Turneri, 
  A. 
  raricostatus, 
  and 
  

   SEgoceras 
  Jamesoni 
  yield 
  most 
  of 
  the 
  72 
  Lower-Lias 
  species 
  known. 
  

   jSo 
  Tabulata 
  or 
  Perforata 
  have 
  as 
  yet 
  been 
  discovered 
  ; 
  and 
  although 
  

   the 
  Bugosa 
  (fam. 
  Stauridae) 
  have 
  occurred 
  in 
  a 
  single 
  instance 
  in 
  the 
  

   L 
  T 
  pper 
  Secondary 
  rocks 
  (Upper 
  Neocomian), 
  yet 
  neither 
  in 
  the 
  Liassic 
  

   nor 
  Oolitic 
  series 
  have 
  any 
  been 
  detected. 
  Holocystis 
  elegans 
  there- 
  

   fore 
  is 
  the 
  only 
  true 
  compound 
  representative 
  of 
  the 
  rugose 
  Corals 
  

   above 
  the 
  Carboniferous 
  Limestone. 
  (Species 
  are 
  said 
  to 
  occur 
  in 
  

   the 
  Tertiary 
  beds 
  and 
  living 
  ; 
  this 
  may 
  require 
  confirmation.) 
  

  

  Prof. 
  P. 
  Martin 
  Duncan, 
  F.R.S., 
  has, 
  however, 
  shown 
  that 
  the 
  

   majority 
  of 
  the 
  Corals 
  of 
  the 
  lowest 
  members 
  of 
  the 
  Lias 
  are 
  pecu- 
  

   liarized 
  by 
  the 
  imperfection 
  of 
  their 
  septal 
  arrangement 
  ; 
  the 
  distinct 
  

   development 
  of 
  definite 
  cycles 
  in 
  six 
  systems 
  is 
  rarely 
  observed 
  ; 
  and 
  

   it 
  would 
  appear 
  that 
  this 
  high 
  organization 
  was 
  not 
  attained 
  in 
  the 
  

   forms 
  which 
  had 
  varied 
  from 
  Palaeozoic 
  into 
  Mesozoic 
  species*. 
  

  

  The 
  remarkable 
  section 
  at 
  Dunravcn, 
  in 
  Glamorganshire, 
  where 
  

   the 
  Sutton 
  Stone 
  is 
  exposed, 
  has 
  yielded 
  corals 
  which 
  Laube 
  has 
  

   described 
  as 
  occurring 
  in 
  the 
  St. 
  Cassian 
  beds 
  of 
  the 
  Trias 
  ; 
  they 
  are 
  

   Thecosmilia 
  rugosa, 
  lihabdophyllia 
  recondita, 
  and 
  Elyastrwa 
  Fischeri. 
  

   The 
  occurrence 
  of 
  these 
  species 
  in 
  the 
  zone 
  of 
  JEgoceras 
  angulatum 
  

   of 
  the 
  Infra 
  Lias 
  is 
  significant 
  and 
  interesting. 
  

  

  The 
  genera 
  which 
  are 
  represented 
  in 
  the 
  zones 
  of 
  ^Egoceras 
  

   jjlanorbis 
  and 
  JEgoceras 
  angulatum 
  are 
  Monilivaltia, 
  BhabdophylUa, 
  

   Thecosmilia, 
  Oppelismilia, 
  Isastrcea, 
  Astroccenia, 
  CyaiJwcoenia, 
  Elyas- 
  

   trcea, 
  Septastrcea, 
  and 
  Latomaiandra. 
  

  

  The 
  luxuriance 
  of 
  the 
  species 
  in 
  the 
  above 
  zone 
  in 
  South 
  Wales 
  

   and 
  one 
  or 
  two 
  other 
  localities 
  shows 
  that 
  the 
  Lias 
  is 
  not 
  the 
  un- 
  

   coralliferous 
  formation 
  it 
  was 
  once 
  believed 
  to 
  be 
  ; 
  and 
  each 
  of 
  the 
  

   succeeding 
  recognized 
  Ammonite 
  zones 
  has 
  a 
  distinct 
  specific 
  coral- 
  

   fauna. 
  The 
  following 
  Table 
  (XIX.) 
  illustrates 
  the 
  distribution 
  

   of 
  the 
  Actinozoa 
  in 
  the 
  zone 
  of 
  JEgoceras 
  angulatum. 
  

  

  * 
  Monog. 
  Brit. 
  Foss. 
  Corals, 
  2nd 
  ser. 
  ; 
  Palseontographical 
  Society, 
  pt. 
  4. 
  no 
  I. 
  

  

  