﻿476 
  IGNEOUS 
  ROCKS 
  IN 
  NORTH 
  PEMBROKESHIRE. 
  [Dec. 
  1 
  897, 
  

  

  that 
  resorption 
  might 
  have 
  produced 
  the 
  effects 
  described. 
  That 
  

   the 
  spherulites 
  were 
  altered 
  in 
  their 
  present 
  position 
  rather 
  than 
  

   during 
  motion 
  after 
  their 
  first 
  formation 
  is, 
  I 
  think, 
  clear 
  from 
  their 
  

   form 
  and 
  mutual 
  arrangement. 
  The 
  truncated 
  edges 
  of 
  the 
  bands 
  

   do 
  not 
  suggest 
  resorption, 
  and 
  the 
  presence 
  of 
  a 
  flow-line 
  between 
  

   two 
  closely 
  adjacent 
  spherulitic 
  bands, 
  and 
  passing 
  a 
  space 
  over 
  

   which 
  resorption 
  must 
  have 
  acted, 
  necessitates 
  after 
  that 
  process, 
  

   when 
  the 
  spherulites 
  would 
  appear 
  as 
  they 
  do 
  now, 
  an 
  amount 
  of 
  

   movement 
  for 
  supposing 
  which, 
  as 
  I 
  have 
  said, 
  there 
  is 
  no 
  

   warrant.— 
  July 
  1st, 
  1897.] 
  

  

  EXPLANATION 
  OF 
  PLATE 
  XXXVI. 
  

  

  Fig. 
  1. 
  Example 
  of 
  the 
  finely 
  fluidal 
  rock 
  from 
  Cam 
  Alw. 
  

  

  Fig. 
  2. 
  Axiolitic 
  rock 
  from 
  Oarn 
  Alw. 
  The 
  axiolites 
  are 
  set 
  in 
  a 
  somewhat 
  

   structureless 
  substance 
  representing 
  a 
  glassy 
  residuum. 
  The 
  fine 
  

   wavy 
  lines 
  in 
  the 
  groundmass 
  are 
  due 
  to 
  the 
  effects 
  of 
  pressure. 
  

  

  Fig. 
  3. 
  Another 
  example 
  of 
  the 
  axiolitic 
  rock 
  from 
  the 
  same 
  locality. 
  

  

  Fig. 
  4. 
  An 
  example 
  of 
  incomplete 
  spherulites 
  from 
  Cam 
  Alw. 
  The 
  imperfect 
  

   form 
  which 
  they 
  present 
  is 
  attributed 
  to 
  flow-movement 
  during 
  

   formation. 
  They 
  contain 
  occasional 
  minute 
  clear 
  spherulites 
  giving 
  a 
  

   fairly 
  definite 
  cross 
  between 
  the 
  two 
  nicols. 
  

  

  Fig. 
  5. 
  Incomplete 
  spherulites 
  from 
  the 
  same 
  locality, 
  but 
  of 
  a 
  different 
  type. 
  

   For 
  these 
  the 
  same 
  explanation 
  is 
  put 
  forward. 
  The 
  absence 
  of 
  

   a 
  definite 
  boundary 
  is 
  seen, 
  so 
  that 
  the 
  outermost 
  part 
  of 
  the 
  

   sphei'ulite 
  grades 
  into 
  the 
  flow-lines; 
  in 
  the 
  centre 
  of 
  the 
  figure 
  it 
  is 
  

   seen 
  that 
  two 
  spherulites 
  in 
  contact 
  have 
  half 
  their 
  outermost 
  zone 
  

   formed, 
  the 
  rest 
  being 
  occupied 
  by 
  flow-lines, 
  while 
  between 
  crossed 
  

   nicols 
  traces 
  of 
  spherulitic 
  structure 
  are 
  almost 
  entirely 
  lost 
  and 
  

   replaced 
  by 
  indications 
  of 
  flow. 
  

  

  Fig. 
  6. 
  One 
  of 
  the 
  more 
  perfectly 
  rounded 
  spheroids 
  resulting 
  from 
  flow- 
  

   brecciation, 
  indications 
  of 
  which 
  are 
  still 
  seen 
  in 
  part 
  of 
  its 
  edge. 
  

   Locality 
  as 
  for 
  preceding 
  figures. 
  

  

  Discussion. 
  

   The 
  President 
  and 
  Prof. 
  Bonnet 
  spoke, 
  and 
  the 
  Author 
  replied. 
  

  

  