﻿124 
  ME. 
  W. 
  H. 
  SHETTBSOLE 
  ON 
  THE 
  EADIOLAEIA 
  OE 
  THE 
  LONDON 
  CLAY. 
  

  

  integrity. 
  Though 
  completely 
  pyritized, 
  they 
  present 
  very 
  smooth, 
  

   even 
  polished 
  surfaces, 
  indicative 
  of 
  their 
  former 
  siliceous 
  condition. 
  

  

  The 
  pseudomorphic 
  change 
  to 
  pyrites 
  seems 
  to 
  have 
  been 
  as 
  

   complete 
  in 
  these 
  Radiolarians 
  as 
  in 
  the 
  Diatoms 
  from 
  the 
  same 
  

   formation. 
  

  

  Sponge-spicules 
  were 
  present 
  in 
  nearly 
  all 
  the 
  washings 
  I 
  ex- 
  

   amined, 
  and 
  in 
  some 
  material 
  from 
  the 
  Queenborough 
  Well, 
  sent 
  

   to 
  Prof. 
  W. 
  J. 
  Sollas, 
  F.Gr.S. 
  &c, 
  he 
  recognized 
  some 
  characteristic 
  

   Tetractinellid 
  forms, 
  one, 
  like 
  the 
  spicules 
  of 
  Stelletta, 
  being 
  a 
  trifid 
  

   fork 
  with 
  bifurcated 
  rays, 
  and 
  another 
  like 
  the 
  calthrops 
  common 
  in 
  

   Pedastrella. 
  

  

  I 
  have 
  to 
  acknowledge 
  the 
  kind 
  assistance 
  rendered 
  by 
  T. 
  Spenser 
  

   Smithson, 
  Esq., 
  of 
  Rochdale, 
  in 
  mounting 
  the 
  specimens 
  exhibited. 
  

  

  Discussion. 
  

  

  The 
  Peesident 
  observed 
  that 
  the 
  particular 
  advantage 
  of 
  a 
  paper 
  

   like 
  the 
  present 
  is 
  that 
  it 
  shows 
  the 
  value 
  of 
  searching. 
  He 
  doubted 
  

   the 
  advisability 
  of 
  coining 
  new 
  names. 
  

  

  Dr. 
  Hinde 
  asked 
  whether 
  the 
  E-adiolaria 
  were 
  uniformly 
  pyri- 
  

   tized; 
  also 
  whether 
  the 
  sponge-spicules 
  had 
  undergone 
  a 
  similar 
  

   change. 
  

  

  Prof. 
  T. 
  Rttpeet 
  Jones 
  commented 
  on 
  the 
  rarity 
  of 
  fossil 
  Hadio- 
  

   laria. 
  Some 
  few 
  have 
  been 
  found 
  in 
  the 
  Chalk. 
  Their 
  pyritization 
  

   would 
  tend 
  to 
  their 
  ready 
  destruction. 
  

  

  The 
  Attthoe, 
  in 
  reply, 
  said 
  that 
  he 
  was 
  not 
  anxious 
  to 
  apply 
  

   new 
  names. 
  He 
  was 
  doubtful 
  whether 
  any 
  silica 
  remained 
  in 
  the 
  

   sponge-spicules 
  or 
  the 
  K-adiolaria, 
  although 
  some 
  has 
  been 
  detected 
  

   in 
  the 
  Diatoms. 
  

  

  