﻿g6 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  paucity 
  of 
  fossils, 
  and 
  evidently 
  were 
  originally 
  deposited 
  under 
  the 
  

   same 
  or 
  similar 
  conditions. 
  It 
  is 
  evident 
  that 
  the 
  great 
  mass 
  of 
  

   the 
  Lincolnshire 
  Oolite 
  was 
  accumulated 
  and 
  deposited 
  under 
  mode- 
  

   rately 
  deep-water 
  conditions. 
  The 
  lower 
  members, 
  however, 
  exhibit 
  

   transitional 
  conditions 
  towards 
  those 
  of 
  the 
  underlying 
  Estuarine 
  

   series. 
  The 
  Arenaceous 
  beds 
  contain 
  much 
  wood 
  and 
  the 
  remains 
  

   of 
  ferns, 
  especially 
  Polypodites 
  Lindleyi, 
  Gopp. 
  (Pecopteris 
  polypo- 
  

   dioides, 
  Lindl.), 
  the 
  whole 
  resembling 
  the 
  conditions 
  prevailing 
  in 
  

   the 
  Lower 
  Sandstones 
  and 
  Shales 
  of 
  east 
  Yorkshire. 
  It 
  is 
  at 
  the 
  

   base 
  of 
  these 
  arenaceous 
  beds 
  that 
  the 
  fissile 
  " 
  Collyweston 
  slates 
  " 
  

   occur, 
  whose 
  position 
  was 
  long 
  misunderstood 
  ; 
  they 
  were 
  wrongly 
  

   assigned 
  to 
  the 
  horizon 
  of 
  the 
  Stonesfield 
  slate, 
  below 
  the 
  true 
  

   Great 
  Oolite. 
  That 
  these 
  remarkable 
  beds 
  were 
  accumulated 
  under 
  

   littoral 
  conditions, 
  or 
  in 
  close 
  proximity 
  to 
  the 
  shore, 
  their 
  fossil 
  

   contents 
  clearly 
  prove. 
  Upwards 
  of 
  50 
  species 
  characterize 
  these 
  

   slates, 
  including 
  6 
  Gasteropoda 
  and 
  46 
  bivalves 
  (26 
  of 
  which 
  are 
  

   Monomyarian 
  and 
  20 
  Dimyarian 
  forms). 
  No 
  mammalian, 
  reptilian, 
  

   or 
  insect 
  remains 
  (so 
  characteristic 
  of 
  the 
  Stonesfield 
  Slate) 
  have 
  

   occurred 
  ; 
  nor 
  do 
  I 
  know 
  of 
  any 
  Brachiopoda. 
  One 
  important 
  uni- 
  

   valve, 
  " 
  Pterocera 
  Bentleyi," 
  essentially 
  characterizes 
  the 
  deposit 
  ; 
  it 
  

   ranges 
  into 
  the 
  limestone 
  above, 
  but 
  is 
  rare. 
  Of 
  bivalves 
  we 
  find 
  

   Gervillia 
  acuta, 
  Pinna 
  cuneata, 
  Trigonia 
  compta, 
  Lucina 
  Wric/htii, 
  

   Myacites 
  scarburgensis, 
  Cardium 
  Buckmani, 
  Pholadomya 
  jidicula, 
  

   and 
  P. 
  ovalis 
  ; 
  Pecten 
  lens 
  and 
  the 
  beautiful 
  fern 
  Polypodites 
  Lindleyi 
  

   specially 
  characterize 
  these 
  slates 
  below 
  the 
  Lincolnshire 
  Limestone. 
  

   Numerically 
  the 
  fauna 
  is 
  thus 
  expressed 
  : 
  — 
  

  

  Genera. 
  Species. 
  

  

  Gasteropoda 
  5 
  .... 
  6 
  

  

  Dimyaria 
  12 
  ,26 
  

  

  Monomyaria 
  10 
  .... 
  20 
  

  

  Asteroidea 
  1 
  .... 
  1 
  

  

  28 
  

  

  53 
  

  

  The 
  following 
  Table 
  (X.) 
  exhibits 
  the 
  chief 
  localities 
  where 
  the 
  

   Lincolnshire 
  Limestone 
  occurs 
  according 
  to 
  Prof. 
  Judd's 
  memoir, 
  and 
  

   the 
  fauna 
  of 
  each 
  locality, 
  the 
  genera 
  and 
  species 
  expressed, 
  as 
  in 
  

   my 
  former 
  Tables, 
  by 
  means 
  of 
  two 
  factors 
  within 
  the 
  square, 
  

   showing 
  both 
  z'oological 
  groups 
  in 
  the 
  column 
  headed 
  by 
  the 
  

   locality, 
  the 
  upper 
  figure 
  indicating 
  the 
  number 
  of 
  genera, 
  and 
  the 
  

   lower 
  the 
  number 
  of 
  species 
  in 
  each 
  locality. 
  

  

  